Chemical compounds

ABSTRACT

The specification relates to compounds of Formula (I): 
                         
and pharmaceutically acceptable salts thereof, to processes and intermediates used for their preparation, pharmaceutical compositions containing them and their use in the treatment of cell proliferative disorders.

This application claims benefit under 35 U.S.C. § 119(e) of the following U.S. Provisional Application Nos. 62/366,173 filed Jul. 25, 2016; 62/382,909 filed Sep. 2, 2016; 62/429,951 filed Dec. 5, 2016; and 62/472,852 filed Mar. 17, 2017. Each of the above listed applications is incorporated by reference herein in its entirety for all purposes.

The specification relates to certain indole compounds and pharmaceutically acceptable salts thereof that selectively down-regulate the estrogen receptor and possess anti-cancer activity. The specification also relates to use of said indole compounds and pharmaceutically acceptable salts thereof in methods of treatment of the human or animal body, for example in prevention or treatment of cancer. The specification also relates to processes and intermediate compounds involved in the preparation of said indole compounds and to pharmaceutical compositions containing them.

Estrogen receptor alpha (ERα, ESR1, NR3A) and estrogen receptor beta (ERβ, ESR2, NR3b) are steroid hormone receptors which are members of the large nuclear receptor family. Structured similarly to all nuclear receptors, ERα is composed of six functional domains (named A-F) (Dahlman-Wright, et al., Pharmacol. Rev., 2006, 58:773-781) and is classified as a ligand-dependent transcription factor because after its association with the specific ligand, (the female sex steroid hormone 17b estradiol (E2)), the complex binds to genomic sequences, named Estrogen Receptor Elements (ERE) and interacts with co-regulators to modulate the transcription of target genes. The ERα gene is located on 6q25.1 and encodes a 595AA protein and multiple isoforms can be produced due to alternative splicing and translational start sites. In addition to the DNA binding domain (Domain C) and the ligand binding domain (Domain E) the receptor contains a N-terminal (A/B) domain, a hinge (D) domain that links the C and E domains and a C-terminal extension (F domain). While the C and E domains of ERα and ERβ are quite conserved (96% and 55% amino acid identity respectively) conservation of the A/B, D and F domains is poor (below 30% amino acid identity). Both receptors are involved in the regulation and development of the female reproductive tract and in addition play roles in the central nervous system, cardiovascular system and in bone metabolism. The genomic action of ERs occurs in the nucleus of the cell when the receptor binds EREs directly (direct activation or classical pathway) or indirectly (indirect activation or non-classical pathway). In the absence of ligand, ERs are associated with heat shock proteins, Hsp90 and Hsp70, and the associated chaperone machinery stabilizes the ligand binding domain (LBD) making it accessible to ligand. Liganded ER dissociates from the heat shock proteins leading to a conformational change in the receptor that allows dimerisation, DNA binding, interaction with co-activators or co-repressors and modulation of target gene expression. In the non-classical pathway, AP-1 and Sp-1 are alternative regulatory DNA sequences used by both isoforms of the receptor to modulate gene expression. In this example, ER does not interact directly with DNA but through associations with other DNA bound transcription factors e.g. c-Jun or c-Fos (Kushner et al., Pure Applied Chemistry 2003, 75:1757-1769). The precise mechanism whereby ER affects gene transcription is poorly understood but appears to be mediated by numerous nuclear factors that are recruited by the DNA bound receptor. The recruitment of co-regulators is primarily mediated by two protein surfaces, AF2 and AF1 which are located in E-domain and the A/B domain respectively. AF1 is regulated by growth factors and its activity depends on the cellular and promoter environment whereas AF2 is entirely dependent on ligand binding for activity. Although the two domains can act independently, maximal ER transcriptional activity is achieved through synergistic interactions via the two domains (Tzukerman, et al., Mol. Endocrinology, 1994, 8:21-30). Although ERs are considered transcription factors they can also act through non-genomic mechanisms as evidenced by rapid ER effects in tissues following E2 administration in a timescale that is considered too fast for a genomic action. It is still unclear if receptors responsible for the rapid actions of estrogen are the same nuclear ERs or distinct G-protein coupled steroid receptors (Warner, et al., Steroids 2006 71:91-95) but an increasing number of E2 induced pathways have been identified e.g. MAPK/ERK pathway and activation of endothelial nitric oxide synthase and PI3K/Akt pathway. In addition to ligand dependent pathways, ERα has been shown to have ligand independent activity through AF-1 which has been associated with stimulation of MAPK through growth factor signalling e.g. insulin like growth factor 1 (IGF-1) and epidermal growth factor (EGF). Activity of AF-1 is dependent on phosphorylation of Ser118 and an example of cross-talk between ER and growth factor signalling is the phosphorylation of Ser 118 by MAPK in response to growth factors such as IGF-1 and EGF (Kato, et al., Science, 1995, 270:1491-1494).

A large number of structurally distinct compounds have been shown to bind to ER. Some compounds such as endogenous ligand E2, act as receptor agonists whereas others competitively inhibit E2 binding and act as receptor antagonists. These compounds can be divided into 2 classes depending on their functional effects. Selective estrogen receptor modulators (SERMs) such as tamoxifen have the ability to act as both receptor agonists and antagonists depending on the cellular and promoter context as well as the ER isoform targeted. For example tamoxifen acts as an antagonist in breast but acts as a partial agonist in bone, the cardiovascular system and uterus. All SERMs appear to act as AF2 antagonists and derive their partial agonist characteristics through AF1. A second group, fulvestrant being an example, are classified as full antagonists and are capable of blocking estrogen activity via the complete inhibition of AF1 and AF2 domains through induction of a unique conformation change in the ligand binding domain (LBD) on compound binding which results in complete abrogation of the interaction between helix 12 and the remainder of the LBD, blocking co-factor recruitment (Wakeling, et al., Cancer Res., 1991, 51:3867-3873; Pike, et al., Structure, 2001, 9:145-153).

Intracellular levels of ERα are down-regulated in the presence of E2 through the ubiquitin/proteosome (Ub/26S) pathway. Polyubiquitinylation of liganded ERα is catalysed by at least three enzymes; the ubiquitin-activating enzyme E1 activated ubiquitin is conjugated by E2 with lysine residues through an isopeptide bond by E3 ubiquitin ligase and polyubiquitinated ERα is then directed to the proteosome for degradation. Although ER-dependent transcription regulation and proteosome-mediated degradation of ER are linked (Lonard, et al., Mol. Cell, 2000 5:939-948), transcription in itself is not required for ERα degradation and assembly of the transcription initiation complex is sufficient to target ERα for nuclear proteosomal degradation. This E2 induced degradation process is believed to necessary for its ability to rapidly activate transcription in response to requirements for cell proliferation, differentiation and metabolism (Stenoien, et al., Mol. Cell Biol., 2001, 21:4404-4412). Fulvestrant is also classified as a selective estrogen receptor down-regulator (SERD), a subset of antagonists that can also induce rapid down-regulation of ERα via the 26S proteosomal pathway. In contrast a SERM such as tamoxifen can increase ERα levels although the effect on transcription is similar to that seen for a SERD.

Approximately 70% of breast cancers express ER and/or progesterone receptors implying the hormone dependence of these tumour cells for growth. Other cancers such as ovarian and endometrial are also thought to be dependent on ERα signalling for growth. Therapies for such patients can inhibit ER signalling either by antagonising ligand binding to ER e.g. tamoxifen which is used to treat early and advanced ER positive breast cancer in both pre and post menopausal setting; antagonising and down-regulating ERα e.g. fulvestrant which is used to treat breast cancer in women which have progressed despite therapy with tamoxifen or aromatase inhibitors; or blocking estrogen synthesis e.g. aromatase inhibitors which are used to treat early and advanced ER positive breast cancer. Although these therapies have had an enormously positive impact on breast cancer treatment, a considerable number of patients whose tumours express ER display de novo resistance to existing ER therapies or develop resistance to these therapies over time. Several distinct mechanisms have been described to explain resistance to first-time tamoxifen therapy which mainly involve the switch from tamoxifen acting as an antagonist to an agonist, either through the lower affinity of certain co-factors binding to the tamoxifen-ERα complex being off-set by over-expression of these co-factors, or through the formation of secondary sites that facilitate the interaction of the tamoxifen-ERα complex with co-factors that normally do not bind to the complex. Resistance could therefore arise as a result of the outgrowth of cells expressing specific co-factors that drive the tamoxifen-ERα activity. There is also the possibility that other growth factor signalling pathways directly activate the ER receptor or co-activators to drive cell proliferation independently of ligand signalling.

More recently, mutations in ESR1 have been identified as a possible resistance mechanism in metastatic ER-positive patient derived tumour samples and patient-derived xenograft models (PDX) at frequencies varying from 17-25%. These mutations are predominantly, but not exclusively, in the ligand-binding domain leading to mutated functional proteins; examples of the amino acid changes include Ser463Pro, Val543Glu, Leu536Arg, Tyr537Ser, Tyr537Asn and Asp538Gly, with changes at amino acid 537 and 538 constituting the majority of the changes currently described. These mutations have been undetected previously in the genomes from primary breast samples characterised in the Cancer Genome Atlas database. Of 390 primary breast cancer samples positive for ER expression not a single mutation was detected in ESR1 (Cancer Genome Atlas Network, 2012 Nature 490: 61-70). The ligand binding domain mutations are thought to have developed as a resistance response to aromatase inhibitor endocrine therapies as these mutant receptors show basal transcriptional activity in the absence of estradiol. The crystal structure of ER, mutated at amino acids 537 and 538, showed that both mutants favoured the agonist conformation of ER by shifting the position of helix 12 to allow co-activator recruitment and thereby mimicking agonist activated wild type ER. Published data has shown that endocrine therapies such as tamoxifen and fulvestrant can still bind to ER mutant and inhibit transcriptional activation to some extent and that fulvestrant is capable of degrading Try537Ser but that higher doses may be needed for full receptor inhibition (Toy et al., Nat. Genetics 2013, 45: 1439-1445; Robinson et al., Nat. Genetics 2013, 45: 144601451; Li, S. et al. Cell Rep. 4, 1116-1130 (2013). It is therefore feasible that certain compounds of the Formula (I) or pharmaceutically acceptable salts thereof (as described hereinafter) will be capable of down-regulating and antagonising mutant ER although it is not known at this stage whether ESR1 mutations are associated with an altered clinical outcome.

Regardless of which resistance mechanism or combination of mechanisms takes place, many are still reliant on ER-dependent activities and removal of the receptor through a SERD mechanism offers the best way of removing the ERα receptor from the cell. Fulvestrant is currently the only SERD approved for clinical use, yet despite its mechanistic properties, the pharmacological properties of the drug have limited its efficacy due to the current limitation of a 500 mg monthly dose which results in less than 50% turnover of the receptor in patient samples compared to the complete down-regulation of the receptor seen in in vitro breast cell line experiments (Wardell, et al., Biochem. Pharm., 2011, 82:122-130). Hence there is a need for new ER targeting agents that have the required pharmaceutical properties and SERD mechanism to provide enhanced benefit in the early, metastatic and acquired resistance setting.

The compounds of the specification have been found to possess potent anti-tumour activity, being useful in inhibiting the uncontrolled cellular proliferation which arises from malignant disease. The compounds of the specification provide an anti-tumour effect by, as a minimum, acting as SERDs. For example, the compounds of the specification may exhibit anti-tumour activity via the ability to down-regulate the estrogen receptor in a number of different breast cancer cell-lines, for example against the MCF-7, CAMA-1, BT474 and/or MDA-MB-134 breast cancer cell-lines. Such compounds may be expected to be more suitable as therapeutic agents, particularly for the treatment of cancer.

The compounds of the specification may also exhibit advantageous physical properties (for example, lower lipophilicity, higher aqueous solubility, higher permeability, lower plasma protein binding, and/or greater chemical stability), and/or favourable toxicity profiles (for example a decreased activity at hERG), and/or favourable metabolic or pharmacokinetic profiles, in comparison with other known SERDs. Such compounds may therefore be especially suitable as therapeutic agents, particularly for the treatment of cancer.

According to one aspect of the specification there is provided a compound of the Formula (I):

wherein: A and G are independently CR¹¹ or N; D and E are independently CH or N; Q is O, NH or NMe; R¹ is CH₂F, CHF₂ or CF₃; R² is H, Me, CH₂F, CHF₂, or CF₃; R³ is H or Me; R⁴ is C₁₋₃ alkyl, CH₂F, CHF₂, CF₃, CH₂CH═CH₂, cyclopropyl or cyclobutyl; R⁵ is H, Me, CH₂F, CHF₂, CF₃, CN, CH₂CN, CH₂OMe, CH₂OH, COOH or CH₂SO₂Me; R⁶ is H, Me, F, CH₂F, CHF₂, CF₃, CN, CH₂CN, CH₂OMe, CH₂OH, COOH or SO₂Me; R⁷ is H, Me or F; R⁸ is H, Me or F; or R⁷ and R⁸ taken together with the carbon atom to which they are attached form a cyclopropyl ring or an oxetane ring; R⁹ and R¹⁰ are each independently selected from H, Me, CH₂OH, CH₂OMe or F; and R¹¹ is independently selected from H, F, Cl, CN, Me or OMe; or a pharmaceutically acceptable salt thereof.

In one embodiment there is provided a compound of Formula (I) as defined above.

In one embodiment there is provided a pharmaceutically acceptable salt of a compound of Formula (I).

In one embodiment D is CH.

In one embodiment E is CH.

In one embodiment both D and E are CH.

In one embodiment both D and E are N.

In one embodiment one of D or E is CH and the other of D or E is N.

In one embodiment A is CR¹¹.

In one embodiment G is CR¹¹.

In one embodiment A is CR¹¹ and G is CR¹¹.

In one embodiment A is CR¹¹ and G is N.

In one embodiment A is N and G is CR¹¹.

In one embodiment R¹¹ is independently selected from H, F, CN or OMe.

In one embodiment R¹¹ is independently selected from H or F.

In one embodiment R¹¹ is independently selected from H, Me or OMe.

In one embodiment R¹¹ is H.

In one embodiment A is CR¹¹ and R¹¹ is H, F, CN or OMe.

In one embodiment A is CR¹¹ and R¹¹ is H, Me or OMe.

In one embodiment G is CR¹¹ and R¹¹ is H, F, CN or OMe.

In one embodiment A is CH and G is CH.

In one embodiment A is C—F and G is C—F.

In one embodiment A is C—F and G is CH.

In one embodiment A is C—OMe and G is CH.

In one embodiment A is C—OMe and G is C—F.

In one embodiment A is C—OMe and G is N.

In one embodiment A is C-Me and G is CH.

In one embodiment A is C—OMe and E is N.

In one embodiment A is C-Me and E is N.

In one embodiment Q is O or NH.

In one embodiment Q is O.

In one embodiment Q is NH.

In one embodiment Q is NMe.

In one embodiment R¹ is CH₂F or CHF₂.

In one embodiment R¹ is CH₂F.

In one embodiment R¹ is CHF₂.

In one embodiment R¹ is CF₃.

In one embodiment R² is H or Me.

In one embodiment R² is H.

In one embodiment R² is Me.

In one embodiment R³ is H.

In one embodiment R³ is Me.

In one embodiment R⁴ is C₁₋₃ alkyl, CHF₂ or cyclopropyl.

In one embodiment R⁴ is C₁₋₃ alkyl or CHF₂.

In one embodiment R⁴ is C₁₋₃ alkyl.

In one embodiment R⁴ is methyl.

In one embodiment R⁴ is CHF₂.

In one embodiment R⁵ is H or Me.

In one embodiment R⁵ is H.

In one embodiment R⁵ is Me.

In one embodiment R⁶ is H, Me, F, CH₂F, CH₂OMe, CH₂OH, COOH or SO₂Me.

In one embodiment R⁶ is H, Me, CH₂OMe or CH₂OH.

In one embodiment R⁶ is H, Me, F or CH₂F.

In one embodiment R⁶ is H, Me, COOH or SO₂Me.

In one embodiment R⁶ is Me or CH₂OMe.

In one embodiment R⁶ is Me.

In one embodiment R⁶ is H.

In one embodiment R⁷ is H.

In one embodiment R⁷ is Me.

In one embodiment R⁷ is F.

In one embodiment R⁸ is Me or F.

In one embodiment R⁸ is Me.

In one embodiment R⁸ is F.

In one embodiment R⁸ is H.

In one embodiment R⁶ is CH₂F, CH₂OMe, CH₂OH or COOH and R⁷ is H.

In one embodiment R⁶ is CH₂F, CH₂OMe, CH₂OH or COOH and R⁷ is F.

In one embodiment R⁶ is H and R⁷ is F.

In one embodiment R⁶ is CH₂F, CH₂OMe, CH₂OH or COOH and R⁸ is Me.

In one embodiment R⁶ is H and R⁸ is F.

In one embodiment R⁷ is H and R⁸ is F.

In one embodiment R⁷ is H and R⁸ is Me.

In one embodiment R⁷ is F and R⁸ is F.

In one embodiment R⁷ is F and R⁸ is Me.

In one embodiment R⁶ is H, R⁷ is F and R⁸ is F.

In one embodiment R⁶ is F and R⁷ and R⁸ taken together with the carbon atom to which they are attached form a cyclopropyl ring or an oxetane ring.

In one embodiment R⁶ is F and R⁷ and R⁸ taken together with the carbon atom to which they are attached form a cyclopropyl ring.

In one embodiment R⁶ is F and R⁷ and R⁸ taken together with the carbon atom to which they are attached form an oxetane ring.

In one embodiment the group —CH(R⁵)—C(R⁶)(R⁷)(R⁸) in the compound of Formula (I) is selected from the group consisting of:

In one embodiment the group —CH(R⁵)—C(R⁶)(R⁷)(R⁸) in the compound of Formula (I) is selected from the group consisting of:

In one embodiment the group —CH(R⁵)—C(R⁶)(R⁷)(R⁸) in the compound of Formula (I) is selected from the group consisting of:

In one embodiment the group —CH(R⁵)—C(R⁶)(R⁷)(R⁸) in the compound of Formula (I) is selected from the group consisting of:

In one embodiment the group —CH(R⁵)—C(R⁶)(R⁷)(R⁸) in the compound of Formula (I) is selected from the group consisting of:

In one embodiment the group —CH(R⁵)—C(R⁶)(R⁷)(R⁸) in the compound of Formula (I) is selected from the group consisting of:

In one embodiment the group —CH(R⁵)—C(R⁶)(R⁷)(R⁸) in the compound of Formula (I) is selected from the group consisting of:

In one embodiment the group —CH(R⁵)—C(R⁶)(R⁷)(R⁸) in the compound of Formula (I) is selected from the group consisting of:

In one embodiment the group —CH(R⁵)—C(R⁶)(R⁷)(R⁸) in the compound of Formula (I) is selected from the group consisting of:

In one embodiment the group —CH(R⁵)—C(R⁶)(R⁷)(R⁸) in the compound of Formula (I) is selected from the group consisting of:

In one embodiment the group —CH(R⁵)—C(R⁶)(R⁷)(R⁸) in the compound of Formula (I) is selected from the group consisting of:

In one embodiment both R⁹ and R¹⁰ are H.

In one embodiment one of R⁹ and R¹⁰ is H, the other of R⁹ and R¹⁰ is Me, F, CH₂OH or CH₂OMe.

In one embodiment one of R⁹ and R¹⁰ is Me, the other of R⁹ and R¹⁰ is H.

In one embodiment R⁹ is H.

In one embodiment R⁹ is Me.

In one embodiment R⁹ is F.

In one embodiment R⁹ is CH₂OH.

In one embodiment R¹⁰ is H.

In one embodiment R¹⁰ is Me.

In one embodiment R¹⁰ is F.

In one embodiment R¹⁰ is CH₂OH.

In one embodiment there is provided a compound of Formula (IA):

wherein: Q is O, NH or NMe; R¹ is CH₂F, CHF₂ or CF₃; R² is H, Me, CH₂F, CHF₂, or CF₃; R³ is H or Me; R⁴ is C₁₋₃ alkyl, CH₂F, CHF₂, CF₃, CH₂CH═CH₂, cyclopropyl or cyclobutyl; R⁵ is H, Me, CH₂F, CHF₂, CF₃, CN, CH₂CN, CH₂OMe, CH₂OH, COOH or CH₂SO₂Me; R⁶ is H, Me, F, CH₂F, CHF₂, CF₃, CN, CH₂CN, CH₂OMe, CH₂OH, COOH or SO₂Me; R⁷ is H, Me or F; R⁸ is H, Me or F; or R⁷ and R⁸ taken together with the carbon atom to which they are attached form a cyclopropyl ring or an oxetane ring; R⁹ and R¹⁰ are each independently selected from H, Me, CH₂OH, CH₂OMe or F; and Ring Y is selected from the group consisting of:

or a pharmaceutically acceptable salt thereof.

In one embodiment there is provided a compound of Formula (IA), or a pharmaceutically acceptable salt thereof, wherein Ring Y is selected from the group consisting of:

In one embodiment there is provided a compound of Formula (IA), or a pharmaceutically acceptable salt thereof, wherein Ring Y is selected from the group consisting of:

In one embodiment there is provided a compound of Formula (IA), or a pharmaceutically acceptable salt thereof, wherein Ring Y is selected from the group consisting of:

In one embodiment there is provided a compound of Formula (IA), or a pharmaceutically acceptable salt thereof, wherein Ring Y is selected from the group consisting of:

In one embodiment there is provided a compound of Formula (IA), or a pharmaceutically acceptable salt thereof, wherein Ring Y is selected from the group consisting of:

In one embodiment there is provided a compound of Formula (IA), or a pharmaceutically acceptable salt thereof, wherein Ring Y is selected from the group consisting of:

In one embodiment there is provided a compound of Formula (IA), or a pharmaceutically acceptable salt thereof, wherein Q is O.

In one embodiment there is provided a compound of Formula (IA), or a pharmaceutically acceptable salt thereof, wherein Q is NH.

In one embodiment there is provided a compound of Formula (IA), or a pharmaceutically acceptable salt thereof, wherein R¹ is CH₂F.

In one embodiment there is provided a compound of Formula (IA), or a pharmaceutically acceptable salt thereof, wherein R¹ is CHF₂.

In one embodiment there is provided a compound of Formula (IA), or a pharmaceutically acceptable salt thereof, wherein R⁵ is H or Me.

In one embodiment there is provided a compound of Formula (IA), or a pharmaceutically acceptable salt thereof, wherein R⁶ is H, Me, F, CH₂F, CH₂OMe, CH₂OH, COOH or SO₂Me.

In one embodiment there is provided a compound of Formula (IA), or a pharmaceutically acceptable salt thereof, wherein R⁶ is H, F or Me, R⁷ is F and R⁸ is F.

In one embodiment there is provided a compound of Formula (IA), or a pharmaceutically acceptable salt thereof, wherein R⁶ is H or F, R⁷ is F and R⁸ is F.

In one embodiment there is provided a compound of Formula (IA), or a pharmaceutically acceptable salt thereof, wherein R⁶ is H, R⁷ is F and R⁸ is F.

In one embodiment there is provided a compound of Formula (IA), or a pharmaceutically acceptable salt thereof, wherein R⁶ is F, R⁷ is F and R⁸ is F.

In one embodiment there is provided a compound of Formula (IA), or a pharmaceutically acceptable salt thereof, wherein R⁶ is F and R⁷ and R⁸ taken together with the carbon atom to which they are attached form a cyclopropyl ring or an oxetane ring. In a further embodiment R⁷ and R⁸ taken together with the carbon atom to which they are attached form a cyclopropyl ring. In a further embodiment R⁷ and R⁸ taken together with the carbon atom to which they are attached form an oxetane ring.

In one embodiment there is provided a compound of Formula (IA), or a pharmaceutically acceptable salt thereof, wherein both R⁹ and R¹⁰ are H.

In one embodiment the group —CH(R⁵)—C(R⁶)(R⁷)(R⁸) in the compound of Formula (IA) is selected from the group consisting of:

In one embodiment the group —CH(R⁵)—C(R⁶)(R⁷)(R⁸) in the compound of Formula (IA) is selected from the group consisting of:

In one embodiment the group —CH(R⁵)—C(R⁶)(R⁷)(R⁸) in the compound of Formula (IA) is selected from the group consisting of:

In one embodiment the group —CH(R⁵)—C(R⁶)(R⁷)(R⁸) in the compound of Formula (IA) is selected from the group consisting of:

In one embodiment the group —CH(R⁵)—C(R⁶)(R⁷)(R⁸) in the compound of Formula (IA) is selected from the group consisting of:

In one embodiment the group —CH(R⁵)—C(R⁶)(R⁷)(R⁸) in the compound of Formula (IA) is selected from the group consisting of:

In one embodiment there is provided a compound of Formula (IB):

wherein: Q is O, NH or NMe; R¹ is CH₂F, CHF₂ or CF₃; R² is H, Me, CH₂F, CHF₂, or CF₃; R³ is H or Me; R⁴ is C₁₋₃ alkyl, CH₂F, CHF₂, CF₃, CH₂CH═CH₂, cyclopropyl or cyclobutyl; R⁹ is H, Me, CH₂OH, CH₂OMe or F; R¹² is selected from the group consisting of:

and Ring Y is selected from the group consisting of:

or a pharmaceutically acceptable salt thereof.

In one embodiment there is provided a compound of Formula (IB), or a pharmaceutically acceptable salt thereof, wherein Ring Y is selected from the group consisting of:

In one embodiment there is provided a compound of Formula (IB), or a pharmaceutically acceptable salt thereof, wherein Ring Y is selected from the group consisting of:

In one embodiment there is provided a compound of Formula (IB), or a pharmaceutically acceptable salt thereof, wherein Ring Y is selected from the group consisting of:

In one embodiment there is provided a compound of Formula (IB), or a pharmaceutically acceptable salt thereof, wherein Ring Y is selected from the group consisting of:

In one embodiment there is provided a compound of Formula (IB), or a pharmaceutically acceptable salt thereof, wherein Ring Y is selected from the group consisting of:

In one embodiment there is provided a compound of Formula (IB), or a pharmaceutically acceptable salt thereof, wherein Q is O.

In one embodiment there is provided a compound of Formula (IB), or a pharmaceutically acceptable salt thereof, wherein R¹² is selected from the group consisting of:

In one embodiment there is provided a compound of Formula (IB), or a pharmaceutically acceptable salt thereof, wherein R¹² is selected from the group consisting of:

In one embodiment the group R¹² in the compound of Formula (IB) is selected from the group consisting of:

In one embodiment the group R¹² in the compound of Formula (IB) is selected from the group consisting of:

In one embodiment the group R¹² in the compound of Formula (IB) is selected from the group consisting of:

In one embodiment the group R¹² in the compound of Formula (IB) is selected from the group consisting of:

In one embodiment the group R⁹ is connected to the remainder of the compound of Formula (IB) as shown below:

In one embodiment the group R⁹ is connected to the remainder of the compound of Formula (IB) as shown below:

In one embodiment there is provided a compound of Formula (IC):

wherein: Q is O, NH or NMe; R¹ is CH₂F, CHF₂ or CF₃; R₂ is H, Me, CH₂F, CHF₂, or CF₃; R³ is H or Me; R⁴ is C₁₋₃ alkyl, CH₂F, CHF₂, CF₃, CH₂CH═CH₂, cyclopropyl or cyclobutyl; R¹⁰ is H, Me, CH₂OH, CH₂OMe or F; R¹² is selected from the group consisting of:

and Ring Y is selected from the group consisting of:

or a pharmaceutically acceptable salt thereof.

In one embodiment there is provided a compound of Formula (IC), or a pharmaceutically acceptable salt thereof, wherein Ring Y is selected from the group consisting of:

In one embodiment there is provided a compound of Formula (IC), or a pharmaceutically acceptable salt thereof, wherein Ring Y is selected from the group consisting of:

In one embodiment there is provided a compound of Formula (IC), or a pharmaceutically acceptable salt thereof, wherein Ring Y is selected from the group consisting of:

In one embodiment there is provided a compound of Formula (IC), or a pharmaceutically acceptable salt thereof, wherein Ring Y is selected from the group consisting of:

In one embodiment there is provided a compound of Formula (IC), or a pharmaceutically acceptable salt thereof, wherein Ring Y is selected from the group consisting of:

In one embodiment there is provided a compound of Formula (IC), or a pharmaceutically acceptable salt thereof, wherein Q is O.

In one embodiment there is provided a compound of Formula (IC), or a pharmaceutically acceptable salt thereof, wherein R¹² is selected from the group consisting of:

In one embodiment there is provided a compound of Formula (IC), or a pharmaceutically acceptable salt thereof, wherein R¹² is selected from the group consisting of:

In one embodiment the group R¹² in the compound of Formula (IC) is selected from the group consisting of:

In one embodiment the group R¹² in the compound of Formula (IC) is selected from the group consisting of:

In one embodiment the group R¹² in the compound of Formula (IC) is selected from the group consisting of:

In one embodiment the group R¹² in the compound of Formula (IC) is selected from the group consisting of:

In one embodiment the group R¹⁰ is connected to the remainder of the compound of Formula (IC) as shown below:

In one embodiment the group R¹⁰ is connected to the remainder of the compound of Formula (IC) as shown below:

In one embodiment there is provided a compound of Formula (IC), or a pharmaceutically acceptable salt thereof, wherein:

R¹ is CH₂F;

R² and R³ are H;

R⁴ is Me;

R¹⁰ is H;

R¹² is selected from the group consisting of:

Q is O or NH; and Ring Y is selected from the group consisting of:

In one embodiment there is provided a compound of Formula (IC), or a pharmaceutically acceptable salt thereof, wherein:

R¹ is CH₂F;

R² and R³ are H;

R⁴ is Me;

R¹⁰ is H;

R¹² is selected from the group consisting of:

Q is O; and Ring Y is:

In a further embodiment there is provided a compound of the Formula (ID):

wherein: A and G are independently CR¹¹ or N; D and E are independently CH or N; Q is O, NH or NMe; R¹ is CH₂F, CHF₂ or CF₃; R² is H, Me, CH₂F, CHF₂, or CF₃; R³ is H or Me; R⁴ is C₁₋₃ alkyl, CH₂F, CHF₂, CF₃, CH₂CH═CH₂, cyclopropyl or cyclobutyl; R⁵ is H, Me, CH₂F, CHF₂, CF₃, CN, CH₂CN, CH₂OMe, CH₂OH, COOH or CH₂SO₂Me; R⁶ is H, Me, F, CH₂F, CHF₂, CF₃, CN, CH₂CN, CH₂OMe, CH₂OH, COOH or SO₂Me; R⁷ is H, Me or F; R⁸ is H, Me or F; or R⁷ and R⁸ taken together with the carbon atom to which they are attached form a cyclopropyl ring or an oxetane ring; R⁹ and R¹⁰ are each independently selected from H, Me, CH₂OH, CH₂OMe or F; and R¹¹ is independently selected from H, F, Cl, CN, Me or OMe; or a pharmaceutically acceptable salt thereof.

In a further embodiment there is provided the compound of Formula (ID) or a pharmaceutically acceptable salt thereof wherein the stereochemistry at the 1-position of the tetrahydro-1H-pyrido[3,4-b]indol-1-yl ring is S.

In a further embodiment there is provided the compound of Formula (ID) or a pharmaceutically acceptable salt thereof wherein the stereochemistry at the 1-position of the tetrahydro-1H-pyrido[3,4-b]indol-1-yl ring is R.

In a further embodiment there is provided the compound of Formula (ID) or a pharmaceutically acceptable salt thereof wherein the stereochemistry at the 3-position of the tetrahydro-1H-pyrido[3,4-b]indol-1-yl ring is S.

In a further embodiment there is provided the compound of Formula (ID) or a pharmaceutically acceptable salt thereof wherein the stereochemistry at the 3-position of the tetrahydro-1H-pyrido[3,4-b]indol-1-yl ring is R.

In one embodiment there is provided a compound of Formula (I), (IA), (IB), (IC) or (ID), or a pharmaceutically acceptable salt thereof, wherein the compound is selected from any of the examples in the specification.

In one embodiment there is provided a compound of Formula (I), (IA), (IB), (IC) or (ID), wherein the compound is selected from the group consisting of:

-   3,3-difluoro-N-(2-(4-((1R,3R)-2-isobutyl-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)phenoxy)ethyl)propan-1-amine; -   3-fluoro-N-(2-(4-((1R,3R)-2-isobutyl-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)phenoxy)ethyl)propan-1-amine; -   N-(2-(3,5-difluoro-4-((1R,3R)-2-(2-fluoro-2-methylpropyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)phenoxy)ethyl)-3,3-difluoropropan-1-amine; -   N-(2-(3,5-difluoro-4-((1R,3R)-2-(2-fluoro-2-methylpropyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)phenoxy)ethyl)-3-fluoropropan-1-amine; -   N-(2-(3,5-difluoro-4-((1R,3R)-2-((3-fluorooxetan-3-yl)methyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)phenoxy)ethyl)-3-fluoropropan-1-amine; -   N-(2-(3,5-difluoro-4-((1R,3R)-2-((1-fluorocyclopropyl)methyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)phenoxy)ethyl)-3-fluoropropan-1-amine; -   3-fluoro-N-(2-((5-((1R,3R)-2-((3-fluorooxetan-3-yl)methyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)-4-methoxypyridin-2-yl)oxy)ethyl)propan-1-amine; -   3-fluoro-N-(2-(4-((1R,3R)-2-((3-fluorooxetan-3-yl)methyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)-3-methoxyphenoxy)ethyl)propan-1-amine; -   N¹-(3,5-difluoro-4-((1R,3R)-2-((1-fluorocyclopropyl)methyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)phenyl)-N²-(3-fluoropropyl)ethane-1,2-diamine; -   3-((1R,3R)-1-(2,6-difluoro-4-(2-((3-fluoropropyl)amino)ethoxy)phenyl)-3-methyl-1,3,4,9-tetrahydro-2H-pyrido[3,4-b]indol-2-yl)-2,2-difluoropropan-1-ol; -   3-fluoro-N-(2-(4-((1R,3R)-2-((1-fluorocyclopropyl)methyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)-3-methoxyphenoxy)ethyl)propan-1-amine; -   N-(2-(4-((1R,3R)-2-(2,2-difluoropropyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)-3,5-difluorophenoxy)ethyl)-3-fluoropropan-1-amine; -   N-(2-(4-((1R,3R)-2-(2,2-difluoroethyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)-3,5-difluorophenoxy)ethyl)-3-fluoropropan-1-amine; -   N-(2-(4-((1R,3R)-2-(2,2-difluoro-3-methoxypropyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)-3,5-difluorophenoxy)ethyl)-3-fluoropropan-1-amine; -   N-(2-(4-((1R,3R)-2-(2,3-difluoropropyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)-3,5-difluorophenoxy)ethyl)-3-fluoropropan-1-amine; -   3-((1R,3R)-1-(2,6-difluoro-4-(2-((3-fluoropropyl)amino)ethoxy)phenyl)-3-methyl-1,3,4,9-tetrahydro-2H-pyrido[3,4-b]indol-2-yl)-2-fluoro-2-methylpropan-1-ol; -   2-(3,5-difluoro-4-((1R,3R)-2-(2-fluoro-2-methylpropyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)phenoxy)-N-(3-fluoropropyl)propan-1-amine; -   3-(3,5-difluoro-4-((1R,3R)-2-(2-fluoro-2-methylpropyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)phenoxy)-2-((3-fluoropropyl)amino)propan-1-ol; -   3-fluoro-N-(2-(3-fluoro-4-((1R,3R)-2-((1-fluorocyclopropyl)methyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)phenoxy)ethyl)propan-1-amine; -   3-fluoro-N-(2-(3-fluoro-4-((1R,3R)-2-((3-fluorooxetan-3-yl)methyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)phenoxy)ethyl)propan-1-amine; -   3-fluoro-N-(2-(4-((1R,3R)-2-((1-fluorocyclopropyl)methyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)phenoxy)ethyl)propan-1-amine; -   3-fluoro-N-(2-(4-((1R,3R)-2-((3-fluorooxetan-3-yl)methyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)phenoxy)ethyl)propan-1-amine; -   N-(2-(4-((1R,3R)-2-(2,3-difluoropropyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)phenoxy)ethyl)-3-fluoropropan-1-amine; -   3-fluoro-N—((S)-1-(4-((1R,3R)-2-((3-fluorooxetan-3-yl)methyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)phenoxy)propan-2-yl)propan-1-amine; -   3-fluoro-N—((R)-1-(4-((1R,3R)-2-((3-fluorooxetan-3-yl)methyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)phenoxy)propan-2-yl)propan-1-amine; -   2-((1R,3R)-2-((1-fluorocyclopropyl)methyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)-5-(2-((3-fluoropropyl)amino)ethoxy)benzonitrile; -   3-fluoro-N-(2-((6-((1S,3R)-2-(2-fluoro-2-methylpropyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)pyridin-3-yl)oxy)ethyl)propan-1-amine; -   3-fluoro-N-(2-((6-((1S,3R)-2-((1-fluorocyclopropyl)methyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)pyridin-3-yl)oxy)ethyl)propan-1-amine; -   3-fluoro-N-(2-((6-((1S,3R)-2-((3-fluorooxetan-3-yl)methyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)pyridin-3-yl)oxy)ethyl)propan-1-amine; -   3-fluoro-N-(2-((5-((1R,3R)-2-((1-fluorocyclopropyl)methyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)pyridin-2-yl)oxy)ethyl)propan-1-amine; -   3-fluoro-N-(2-((5-((1R,3R)-2-((3-fluorooxetan-3-yl)methyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)pyridin-2-yl)oxy)ethyl)propan-1-amine; -   3-fluoro-N-(2-((6-((1S,3R)-2-(2-fluoro-2-methylpropyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)-5-methoxypyridin-3-yl)oxy)ethyl)propan-1-amine; -   3-fluoro-N-(2-((5-((1R,3R)-2-(2-fluoro-2-methylpropyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)-4-methoxypyridin-2-yl)oxy)ethyl)propan-1-amine; -   3-fluoro-N-(2-((5-((1R,3R)-2-((1-fluorocyclopropyl)methyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)-4-methoxypyridin-2-yl)oxy)ethyl)propan-1-amine; -   3-fluoro-N-(2-((5-((1S,3R)-2-(2-fluoro-2-methylpropyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)pyrazin-2-yl)oxy)ethyl)propan-1-amine;     and -   3-fluoro-N-(2-((2-((1S,3R)-2-(2-fluoro-2-methylpropyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)pyrimidin-5-yl)oxy)ethyl)propan-1-amine;     or a pharmaceutically acceptable salt thereof.

In one embodiment there is provided a compound of Formula (I), (IA), (IB), (IC) or (ID), wherein the compound is selected from the group consisting of:

-   3,3-difluoro-N-(2-(4-((1R,3R)-2-isobutyl-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)phenoxy)ethyl)propan-1-amine; -   3-fluoro-N-(2-(4-((1R,3R)-2-isobutyl-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)phenoxy)ethyl)propan-1-amine; -   N-(2-(3,5-difluoro-4-((1R,3R)-2-(2-fluoro-2-methylpropyl)-3-methyl-2,3,     4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)phenoxy)ethyl)-3,3-difluoropropan-1-amine; -   N-(2-(3,5-difluoro-4-((1R,3R)-2-(2-fluoro-2-methylpropyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)phenoxy)ethyl)-3-fluoropropan-1-amine; -   N-(2-(3,5-difluoro-4-((1R,3R)-2-((3-fluorooxetan-3-yl)methyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)phenoxy)ethyl)-3-fluoropropan-1-amine; -   N-(2-(3,5-difluoro-4-((1R,3R)-2-((1-fluorocyclopropyl)methyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)phenoxy)ethyl)-3-fluoropropan-1-amine; -   3-fluoro-N-(2-((5-((1R,3R)-2-((3-fluorooxetan-3-yl)methyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)-4-methoxypyridin-2-yl)oxy)ethyl)propan-1-amine; -   3-fluoro-N-(2-(4-((1R,3R)-2-((3-fluorooxetan-3-yl)methyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)-3-methoxyphenoxy)ethyl)propan-1-amine; -   N¹-(3,5-difluoro-4-((1R,3R)-2-((1-fluorocyclopropyl)methyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)phenyl)-N²-(3-fluoropropyl)ethane-1,2-diamine; -   3-((1R,3R)-1-(2,6-difluoro-4-(2-((3-fluoropropyl)amino)ethoxy)phenyl)-3-methyl-1,3,4,9-tetrahydro-2H-pyrido[3,4-b]indol-2-yl)-2,2-difluoropropan-1-ol;     and -   3-fluoro-N-(2-(4-((1R,3R)-2-((1-fluorocyclopropyl)methyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)-3-methoxyphenoxy)ethyl)propan-1-amine;     or a pharmaceutically acceptable salt thereof.

In one embodiment there is provided a compound of Formula (I), (IA), (IB), (IC) or (ID), wherein the compound is selected from the group consisting of:

-   3,3-difluoro-N-(2-(4-((1R,3R)-2-isobutyl-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)phenoxy)ethyl)propan-1-amine; -   3-fluoro-N-(2-(4-((1R,3R)-2-isobutyl-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)phenoxy)ethyl)propan-1-amine; -   N-(2-(3,5-difluoro-4-((1R,3R)-2-(2-fluoro-2-methylpropyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)phenoxy)ethyl)-3,3-difluoropropan-1-amine; -   N-(2-(3,5-difluoro-4-((1R,3R)-2-(2-fluoro-2-methylpropyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)phenoxy)ethyl)-3-fluoropropan-1-amine; -   N-(2-(3,5-difluoro-4-((1R,3R)-2-((3-fluorooxetan-3-yl)methyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)phenoxy)ethyl)-3-fluoropropan-1-amine;     and -   N-(2-(3,5-difluoro-4-((1R,3R)-2-((1-fluorocyclopropyl)methyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)phenoxy)ethyl)-3-fluoropropan-1-amine;

In one embodiment there is provided a compound of Formula (I), (IA), (IB), (IC) or (ID), wherein the compound is selected from the group consisting of:

-   3,3-difluoro-N-(2-(4-((1R,3R)-2-isobutyl-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)phenoxy)ethyl)propan-1-amine; -   3-fluoro-N-(2-(4-((1R,3R)-2-isobutyl-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)phenoxy)ethyl)propan-1-amine; -   N-(2-(3,5-difluoro-4-((1R,3R)-2-(2-fluoro-2-methylpropyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)phenoxy)ethyl)-3,3-difluoropropan-1-amine;     and -   N-(2-(3,5-difluoro-4-((1R,3R)-2-(2-fluoro-2-methylpropyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)phenoxy)ethyl)-3-fluoropropan-1-amine;     or a pharmaceutically acceptable salt thereof.

In one embodiment there is provided a compound of Formula (I), wherein the compound is selected from the group consisting of:

-   N-(2-((5-(2-(2,2-difluoroethyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)-4-methoxypyridin-2-yl)oxy)ethyl)-3-fluoropropan-1-amine;     and -   3-fluoro-N-[2-({4-methoxy-5-[3-methyl-2-(2,2,2-trifluoroethyl)-2,3,4,9-tetrahydro-1H-beta-carbolin-1-yl]-2-pyridinyl}oxy)ethyl]-1-propanamine;     or a pharmaceutically acceptable salt thereof.

In one embodiment there is provided a compound of Formula (I), (IA), (IB), (IC) or (ID), wherein the compound is selected from the group consisting of:

-   N-(2-((5-((1R,3R)-2-(2,2-difluoroethyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)-4-methoxypyridin-2-yl)oxy)ethyl)-3-fluoropropan-1-amine;     and -   3-fluoro-N-[2-({4-methoxy-5-[(1R,3R)-3-methyl-2-(2,2,2-trifluoroethyl)-2,3,4,9-tetrahydro-1H-beta-carbolin-1-yl]-2-pyridinyl}oxy)ethyl]-1-propanamine;     or a pharmaceutically acceptable salt thereof.

In one embodiment there is provided a compound of Formula (I), (IA), (IB), (IC) or (ID), wherein the compound is selected from the group consisting of:

-   N-(2-((5-((1R,3R)-2-(2,2-difluoroethyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)-4-methoxypyridin-2-yl)oxy)ethyl)-3-fluoropropan-1-amine;     or a pharmaceutically acceptable salt thereof.

In one embodiment there is provided a compound of Formula (I), (IA), (IB), (IC) or (ID), wherein the compound is selected from the group consisting of:

-   3-Fluoro-N-(2-((4-methoxy-5-((1R,3R)-3-methyl-2-(2,2,2-trifluoroethyl)-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)pyridin-2-yl)oxy)ethyl)propan-1-amine; -   N-(2-((5-((1R,3R)-2-(2,2-Difluoropropyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)-4-methoxypyridin-2-yl)oxy)ethyl)-3-fluoropropan-1-amine; -   N-(2-(4-((1R,3R)-2-(2,2-Difluoroethyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)-3-methoxyphenoxy)ethyl)-3-fluoropropan-1-amine; -   N1-(3,5-difluoro-4-((1R,3R)-2-((3-fluorooxetan-3-yl)methyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)phenyl)-N2-(3-fluoropropyl)ethane-1,2-diamine; -   N1-(3,5-difluoro-4-((1R,3R)-2-((1-fluorocyclopropyl)methyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)phenyl)-N2-(3-fluoropropyl)-N1-methylethane-1,2-diamine; -   3-((1R,3R)-1-(2,6-difluoro-4-((2-((3-fluoropropyl)amino)ethyl)amino)phenyl)-3-methyl-1,3,4,9-tetrahydro-2H-pyrido[3,4-b]indol-2-yl)-2,2-difluoropropan-1-ol; -   N1-(4-((1R,3R)-2-((3-fluorooxetan-3-yl)methyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)-3-methoxyphenyl)-N2-(3-fluoropropyl)ethane-1,2-diamine; -   N-(2-(4-((1R,3R)-2-(2,2-difluoroethyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)-3-fluorophenoxy)ethyl)-3-fluoropropan-1-amine; -   N1-(4-((1R,3R)-2-(2,2-difluoroethyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)-3,5-difluorophenyl)-N2-(3-fluoropropyl)-N1-methylethane-1,2-diamine; -   N-(2-(3,5-difluoro-4-((1R,3R)-2-(2-fluoro-3-methoxy-2-methylpropyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)phenoxy)ethyl)-3-fluoropropan-1-amine; -   N-(2-(3,5-difluoro-4-((1R,3R)-2-(2-fluoro-3-methoxy-2-methylpropyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)phenoxy)ethyl)-3-fluoropropan-1-amine; -   3-(3,5-difluoro-4-((1R,3R)-2-(2-fluoro-2-methylpropyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)phenoxy)-2-((3-fluoropropyl)amino)propan-1-ol; -   3-(3,5-difluoro-4-((1R,3R)-2-(2-fluoro-2-methylpropyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)phenoxy)-2-((3-fluoropropyl)amino)propan-1-ol; -   N1-(4-((1R,3R)-2-(2,2-difluoroethyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)-3,5-difluorophenyl)-N2-(3-fluoropropyl)ethane-1,2-diamine; -   N-(2-(4-((1R,3R)-2-(2,2-difluoropropyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)-3-fluorophenoxy)ethyl)-3-fluoropropan-1-amine; -   N-(2-(4-((1R,3R)-2-(2,2-difluoroethyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)phenoxy)ethyl)-3-fluoropropan-1-amine; -   N-(2-(4-((1R,3R)-2-(2,2-difluoropropyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)phenoxy)ethyl)-3-fluoropropan-1-amine; -   2,2-difluoro-3-((1R,3R)-1-(4-((2-((3-fluoropropyl)amino)ethoxy)-2-methoxyphenyl)-3-methyl-1,3,4,9-tetrahydro-2H-pyrido[3,4-b]indol-2-yl)propan-1-ol; -   2,2-difluoro-3-((1R,3R)-1-(4-((2-((3-fluoropropyl)amino)ethyl)amino)-2-methoxyphenyl)-3-methyl-1,3,4,9-tetrahydro-2H-pyrido[3,4-b]indol-2-yl)propan-1-ol; -   N1-(4-((1R,3R)-2-((1-fluorocyclopropyl)methyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)-3-methoxyphenyl)-N2-(3-fluoropropyl)ethane-1,2-diamine; -   N1-(4-((1R,3R)-2-(2,2-difluoroethyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)-3-methoxyphenyl)-N2-(3-fluoropropyl)ethane-1,2-diamine; -   3-fluoro-N-(2-((4-fluoro-5-((1R,3R)-2-((3-fluorooxetan-3-yl)methyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)pyridin-2-yl)oxy)ethyl)propan-1-amine; -   N-(2-((5-((1R,3R)-2-(2,2-difluoroethyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)-4-methylpyridin-2-yl)oxy)ethyl)-3-fluoropropan-1-amine; -   2,2-difluoro-3-((1R,3R)-1-(6-(2-((3-fluoropropyl)amino)ethoxy)-4-methoxypyridin-3-yl)-3-methyl-1,3,4,9-tetrahydro-2H-pyrido[3,4-b]indol-2-yl)propan-1-ol; -   2,2-difluoro-3-((1R,3R)-1-(6-((2-((3-fluoropropyl)amino)ethyl)amino)-4-methoxypyridin-3-yl)-3-methyl-1,3,4,9-tetrahydro-2H-pyrido[3,4-b]indol-2-yl)propan-1-ol; -   N1-(5-((1R,3R)-2-((3-fluorooxetan-3-yl)methyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)-4-methoxypyridin-2-yl)-N2-(3-fluoropropyl)ethane-1,2-diamine; -   N1-(5-((1R,3R)-2-(2,2-difluoroethyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)-4-methoxypyridin-2-yl)-N2-(3-fluoropropyl)ethane-1,2-diamine; -   is     N1-(5-((1R,3R)-2-(2,2-difluoropropyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)-4-methoxypyridin-2-yl)-N2-(3-fluoropropyl)ethane-1,2-diamine; -   2,2-difluoro-3-((1     S,3R)-1-(5-(2-((3-fluoropropyl)amino)ethoxy)pyrazin-2-yl)-3-methyl-1,3,4,9-tetrahydro-2H-pyrido[3,4-b]indol-2-yl)propan-1-ol; -   N-(2-((5-((1     S,3R)-2-(2,2-difluoroethyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)pyrazin-2-yl)oxy)ethyl)-3-fluoropropan-1-amine; -   N1-(5-((1     S,3R)-2-(2,2-difluoroethyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)pyrazin-2-yl)-N2-(3-fluoropropyl)ethane-1,2-diamine; -   N-(2-(3,5-difluoro-4-((1R,3R)-2-((3-(fluoromethyl)oxetan-3-yl)methyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)phenoxy)ethyl)-3-fluoropropan-1-amine; -   3-fluoro-N-(2-(3-methoxy-4-((1R,3R)-3-methyl-2-(2,2,2-trifluoroethyl)-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)phenoxy)ethyl)propan-1-amine; -   N-(2-(4-((1R,3R)-2-(2,2-difluoropropyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)-3-methoxyphenoxy)ethyl)-3-fluoropropan-1-amine; -   N-(2-((5-((1R,3R)-2-(2,2-difluoroethyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)-6-methoxypyridin-2-yl)oxy)ethyl)-3-fluoropropan-1-amine; -   N1-(5-((1R,3R)-2-(2,2-difluoroethyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)-6-methoxypyridin-2-yl)-N2-(3-fluoropropyl)ethane-1,2-diamine; -   N-(2-((5-((1R,3R)-2-(2,2-difluoropropyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)-6-methoxypyridin-2-yl)oxy)ethyl)-3-fluoropropan-1-amine;     and -   N1-(5-((1R,3R)-2-(2,2-difluoropropyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)-6-methoxypyridin-2-yl)-N2-(3-fluoropropyl)ethane-1,2-diamine;     or a pharmaceutically acceptable salt thereof.

The C₁₋₃ alkyl group may be branched or unbranched. Examples of suitable C₁₋₃ alkyl groups include methyl (Me), ethyl (Et), n-propyl (n-Pr) or i-propyl (i-Pr).

For the avoidance of doubt, in the compound of Formula (I), (IA), (IB), (IC) or (ID), the substituents R⁹ and R¹⁰ may each be substituted at either position of the respective ethyl chain with which they are associated. Therefore, by way of example only, the R⁹ substituent may be attached in the two possible positions as shown below:

For the further avoidance of doubt, the use of

in formulas of this specification denotes the point of attachment between different groups.

For the further avoidance of doubt, where multiple substituents are independently selected from a given group, the selected substituents may comprise the same substituents or different substituents from within the given group.

The compounds of Formula (I), (IA), (IB), (IC) or (ID) have two or more chiral centres and it will be recognised that the compound of Formula (I), (IA), (IB), (IC) or (ID) may be prepared, isolated and/or supplied with or without the presence, in addition, of one or more of the other possible enantiomeric and/or diastereomeric isomers of the compound of Formula (I), (IA), (IB), (IC) or (ID) in any relative proportions. The preparation of enantioenriched/enantiopure and/or diastereoenriched/diastereopure compounds may be carried out by standard techniques of organic chemistry that are well known in the art, for example by synthesis from enantioenriched or enantiopure starting materials, use of an appropriate enantioenriched or enantiopure catalyst during synthesis, and/or by resolution of a racemic or partially enriched mixture of stereoisomers, for example via chiral chromatography.

For use in a pharmaceutical context it may be preferable to provide a compound of Formula (I), (IA), (IB), (IC) or (ID), or a pharmaceutically acceptable salt thereof, without large amounts of the other stereoisomeric forms being present.

Accordingly, in one embodiment there is provided a composition comprising a compound of Formula (I), (IA), (IB), (IC) or (ID), or a pharmaceutically acceptable salt thereof, optionally together with one or more of the other stereoisomeric forms of the compound of Formula (I), (IA), (IB), (IC) or (ID), or pharmaceutically acceptable salt thereof, wherein the compound of Formula (I), (IA), (IB), (IC) or (ID), or pharmaceutically acceptable salt thereof, is present within the composition with a diastereomeric excess (% de) of ≥90%.

In a further embodiment the % de in the above-mentioned composition is ≥95%.

In a further embodiment the % de in the above-mentioned composition is ≥98%.

In a further embodiment the % de in the above-mentioned composition is ≥99%.

In a further embodiment there is provided a composition comprising a compound of Formula (I), (IA), (IB), (IC) or (ID), or a pharmaceutically acceptable salt thereof, optionally together with one or more of the other stereoisomeric forms of the compound of Formula (I), (IA), (IB), (IC) or (ID), or pharmaceutically acceptable salt thereof, wherein the compound of Formula (I), (IA), (IB), (IC) or (ID), or pharmaceutically acceptable salt thereof is present within the composition with an enantiomeric excess (% ee) of ≥90%.

In a further embodiment the % ee in the above-mentioned composition is ≥95%.

In a further embodiment the % ee in the above-mentioned composition is ≥98%.

In a further embodiment the % ee in the above-mentioned composition is ≥99%.

In a further embodiment there is provided a composition comprising a compound of Formula (I), (IA), (IB), (IC) or (ID), or a pharmaceutically acceptable salt thereof, optionally together with one or more of the other stereoisomeric forms of the compound of Formula (I), (IA), (IB), (IC) or (ID), or pharmaceutically acceptable salt thereof, wherein the compound of Formula (I), (IA), (IB), (IC) or (ID), or pharmaceutically acceptable salt thereof is present within the composition with an enantiomeric excess (% ee) of ≥90% and a diastereomeric excess (% de) of ≥90%.

In further embodiments of the above-mentioned composition the % ee and % de may take any combination of values as listed below:

-   -   The % ee is ≤5% and the % de is ≥80%.     -   The % ee is ≤5% and the % de is ≥90%.     -   The % ee is ≤5% and the % de is ≥95%.     -   The % ee is ≤5% and the % de is ≥98%.     -   The % ee is ≥95% and the % de is ≥95%.     -   The % ee is ≥98% and the % de is ≥98%.     -   The % ee is ≥99% and the % de is ≥99%.

In a further embodiment there is provided a pharmaceutical composition which comprises a compound of the Formula (I), (IA), (IB), (IC) or (ID), or a pharmaceutically acceptable salt thereof, in association with a pharmaceutically acceptable excipient.

In one embodiment there is provided a pharmaceutical composition which comprises a compound of the Formula (I), (IA), (IB), (IC) or (ID), or a pharmaceutically acceptable salt thereof, in association with a pharmaceutically acceptable excipient, optionally further comprising one or more of the other stereoisomeric forms of the compound of Formula (I), (IA), (IB), (IC) or (ID), or pharmaceutically acceptable salt thereof, wherein the compound of Formula (I), (IA), (IB), (IC) or (ID), or pharmaceutically acceptable salt thereof, is present within the composition with an enantiomeric excess (% ee) of ≥90%.

In a further embodiment the % ee in the above-mentioned composition is ≥95%.

In a further embodiment the % ee in the above-mentioned composition is ≥98%.

In a further embodiment the % ee in the above-mentioned composition is ≥99%.

In one embodiment there is provided a pharmaceutical composition which comprises a compound of the Formula (I), (IA), (IB), (IC) or (ID), or a pharmaceutically acceptable salt thereof, in association with a pharmaceutically acceptable excipient, optionally further comprising one or more of the other stereoisomeric forms of the compound of Formula (I), (IA), (IB), (IC) or (ID), or pharmaceutically acceptable salt thereof, wherein the compound of Formula (I), (IA), (IB), (IC) or (ID), or pharmaceutically acceptable salt thereof, is present within the composition with a diastereomeric excess (% de) of ≥90%.

In a further embodiment the % de in the above-mentioned composition is ≥95%.

In a further embodiment the % de in the above-mentioned composition is ≥98%.

In a further embodiment the % de in the above-mentioned composition is ≥99%.

In one embodiment there is provided a pharmaceutical composition which comprises a compound of the Formula (I), (IA), (IB), (IC) or (ID), or a pharmaceutically acceptable salt thereof, in association with a pharmaceutically acceptable excipient, optionally further comprising one or more of the other stereoisomeric forms of the compound of Formula (I), (IA), (IB), (IC) or (ID), or pharmaceutically acceptable salt thereof, wherein the compound of Formula (I), (IA), (IB), (IC) or (ID), or pharmaceutically acceptable salt thereof, is present within the composition with an enantiomeric excess (% ee) of ≥90% and a diastereomeric excess (% de) of ≥90%.

In further embodiments of the above-mentioned pharmaceutical composition the % ee and % de may take any combination of values as listed below:

-   -   The % ee is ≥95% and the % de is ≥95%.     -   The % ee is ≥98% and the % de is ≥98%.     -   The % ee is ≥99% and the % de is ≥99%.

The compounds of Formula (I), (IA), (IB), (IC) or (ID), and pharmaceutically acceptable salts thereof may be prepared, used or supplied in amorphous form, crystalline form, or semicrystalline form and any given compound of Formula (I), (IA), (IB), (IC) or (ID), or pharmaceutically acceptable salt thereof, may be capable of being formed into more than one crystalline/polymorphic form, including hydrated (e.g. hemi-hydrate, a mono-hydrate, a di-hydrate, a tri-hydrate or other stoichiometry of hydrate) and/or solvated forms. It is to be understood that the present specification encompasses any and all such solid forms of the compound of Formula (I), (IA), (IB), (IC) or (ID), and pharmaceutically acceptable salts thereof.

In further embodiments there is provided a compound of Formula (I), (IA), (IB), (IC) or (ID), which is obtainable by the methods described in the ‘Examples’ section hereinafter.

The present specification is intended to include all isotopes of atoms occurring in the present compounds. Isotopes will be understood to include those atoms having the same atomic number but different mass numbers. For example, isotopes of hydrogen include tritium and deuterium. Isotopes of carbon include ¹³C and ¹⁴C. In a particular embodiment there is provided a compound of Formula (I) (IA), (IB), (IC) or (ID), wherein R² is deuterium.

A suitable pharmaceutically acceptable salt of a compound of the Formula (I), (IA), (IB), (IC) or (ID), is, for example, an acid addition salt. A suitable pharmaceutically acceptable salt of a compound of the Formula (I), (IA), (IB), (IC) or (ID), may be, for example, an acid-addition salt of a compound of the Formula (I), (IA), (IB), (IC) or (ID), for example an acid-addition salt with an inorganic or organic acid such as hydrochloric acid, hydrobromic acid, sulphuric acid or trifluoroacetic acid. Pharmaceutically acceptable salts of a compound of the Formula (I), (IA), (IB), (IC) or (ID), may also be an acid-addition salt with an acid such as one of the following: acetic acid, adipic acid, benzene sulfonic acid, benzoic acid, cinnamic acid, citric acid, D,L-lactic acid, ethane disulfonic acid, ethane sulfonic acid, fumaric acid, L-tartaric acid, maleic acid, malic acid, malonic acid, methane sulfonic acid, napadisylic acid, phosphoric acid, saccharin, succinic acid, p-toluenesulfonic acid or toluene sulfonic acid.

A further suitable pharmaceutically acceptable salt of a compound of Formula (I), (IA), (IB), (IC) or (ID) is a 2-methoxybenzoate salt, ie. an acid-addition salt with 2-methoxybenzoic acid.

A further suitable pharmaceutically acceptable salt of a compound of the Formula (I), (IA), (IB), (IC) or (ID), is, for example, a salt formed within the human or animal body after administration of a compound of the Formula (I), (IA), (IB), (IC) or (ID), to said human or animal body.

The compound of Formula (I), (IA), (IB), (IC) or (ID), or pharmaceutically acceptable salt thereof may be prepared as a co-crystal solid form. It is to be understood that a pharmaceutically acceptable co-crystal of a compound of the Formula (I), (IA), (IB), (IC) or (ID), or pharmaceutically acceptable salts thereof, form an aspect of the present specification.

The specific solid forms described herein provide X-ray powder diffraction patterns substantially the same as the X-ray powder diffraction patterns shown in the Figures and have the various 2-theta values as shown in the Tables included herein. It will be understood that the 2-theta values of a X-ray powder diffraction pattern may vary slightly from one machine to another or from one sample to another, and so the values quoted are not to be construed as absolute.

It is known that an X-ray powder diffraction pattern may be obtained which has one or more measurement errors depending on measurement conditions (such as equipment or machine used). In particular, it is generally known that intensities in an X-ray powder diffraction pattern may fluctuate depending on measurement conditions. Therefore it should be understood that the solid forms of the present specification are not limited to the crystals that provide X-ray powder diffraction patterns that are identical to the X-ray powder diffraction pattern shown in the Figures, and any crystals providing X-ray powder diffraction patterns substantially the same as those shown in the Figures fall within the scope of the present specification. A person skilled in the art of X-ray powder diffraction is able to judge the substantial identity of X-ray powder diffraction patterns.

Persons skilled in the art of X-ray powder diffraction will realise that the relative intensity of peaks can be affected by, for example, grains above 30 μm in size and non-unitary aspect ratios, which may affect analysis of samples. The skilled person will also realise that the position of reflections can be affected by the precise height at which the sample sits in the diffractometer and the zero calibration of the diffractometer. The surface planarity of the sample may also have a small effect. Hence the diffraction pattern data presented are not to be taken as absolute values. (Jenkins, R & Snyder, R. L. ‘Introduction to X-Ray Powder Diffractometry’ John Wiley & Sons 1996; Bunn, C. W. (1948), Chemical Crystallography, Clarendon Press, London; Klug, H. P. & Alexander, L. E. (1974), X-Ray Diffraction Procedures).

Generally, a measurement error of a diffraction angle in an X-ray powder diffractogram is approximately plus or minus 0.2° 2-theta, and such degree of a measurement error should be taken into account when considering the X-ray powder diffraction pattern in the Figures and when reading data contained in the Tables included herein. Furthermore, it should be understood that intensities might fluctuate depending on experimental conditions and sample preparation (preferred orientation).

In this specification the form of the compound N-(2-((5-((1R,3R)-2-(2,2-difluoroethyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)-4-methoxypyridin-2-yl)oxy)ethyl)-3-fluoropropan-1-amine was initially found to be an amorphous solid. A useful crystalline polymorphic form in the form of a 2-methoxybenzoate salt of the compound (hereinafter referred to as Salt X) has subsequently been produced using the conditions described in the experimental section.

Therefore in a further aspect of the specification there is provided polymorphic Form A of Salt X. This polymorphic form may be characterised in that it provides at least one of the following 2θ values measured using CuKa radiation: 9.2, 22.8 and 27.1.

Polymorphic Form A of Salt X is characterised in providing an X-ray powder diffraction pattern, substantially as shown in FIG. 1.

Ten X-Ray powder diffraction peaks for this polymorphic form [Angle 2-theta (2θ), Intensity (%)] are: 9.2 (100%), 22.8 (56.0%), 27.1 (18.9%), 13.8 (16.8%), 19.7 (12.0%), 18.4 (11.1%), 27.7 (10.8%), 17.3 (10.0%), 21.4 (9.4%) and 21.1 (8.7%).

According to the present specification there is provided the polymorphic Form A of Salt X, which has an X-ray powder diffraction pattern with at least one specific peak at about 2-theta=9.2°.

According to the present specification there is provided the polymorphic Form A of Salt X, which has an X-ray powder diffraction pattern with at least one specific peak at about 2-theta=22.8°.

According to the present specification there is provided the polymorphic Form A of Salt X, which has an X-ray powder diffraction pattern with at least one specific peak at about 2-theta=27.1°.

According to the present specification there is provided the polymorphic Form A of Salt X, which has an X-ray powder diffraction pattern with at least two specific peaks at about 2-theta=9.2° and 22.8°.

According to the present specification there is provided the polymorphic Form A of Salt X, which has an X-ray powder diffraction pattern with specific peaks at about 2-theta=9.2, 22.8, 27.1, 13.8, 19.7, 18.4, 27.7, 17.3, 21.4 and 21.1°.

According to the present specification there is provided polymorphic Form A of Salt X which has an X-ray powder diffraction pattern substantially the same as the X-ray powder diffraction pattern shown in FIG. 1.

According to the present specification there is provided polymorphic Form A of Salt X, which has an X-ray powder diffraction pattern with at least one specific peak at 2-theta=9.2° plus or minus 0.2° 2-theta.

According to the present specification there is provided a polymorphic Form A of Salt X, which has an X-ray powder diffraction pattern with at least one specific peak at 2-theta=22.8° plus or minus 0.2° 2-theta.

According to the present specification there is provided the polymorphic Form A of Salt X, which has an X-ray powder diffraction pattern with at least two specific peaks at 2-theta=9.2° and 22.8° wherein said values may be plus or minus 0.2° 2-theta.

According to the present specification there is provided a polymorphic Form A of Salt X, which has an X-ray powder diffraction pattern with specific peaks at 2-theta=9.2, 22.8, 27.1, 13.8, 19.7, 18.4, 27.7, 17.3, 21.4 and 21.1° wherein said values may be plus or minus 0.2° 2-theta.

It is to be understood that a suitable pharmaceutically acceptable pro-drug of a compound of the Formula (I), (IA), (IB), (IC) or (ID), also forms an aspect of the present specification. Accordingly, the compounds of the specification may be administered in the form of a pro-drug, which is a compound that is broken down in the human or animal body to release a compound of the specification. A pro-drug may be used to alter the physical properties and/or the pharmacokinetic properties of a compound of the specification. A pro-drug can be formed when the compound of the specification contains a suitable group or substituent to which a property-modifying group can be attached. Examples of pro-drugs include in-vivo cleavable ester or amide derivatives of the compound of the Formula (I), (IA), (IB), (IC) or (ID).

Accordingly, one aspect of the present specification includes those compounds of Formula (I), (IA), (IB), (IC) or (ID), as defined hereinbefore when made available by organic synthesis and when made available within the human or animal body by way of cleavage of a pro-drug thereof. Accordingly, the present specification includes those compounds of the Formula (I), (IA), (IB), (IC) or (ID), that are produced by organic synthetic means and also such compounds that are produced in the human or animal body by way of metabolism of a precursor compound, that is a compound of the Formula (I), (IA), (IB), (IC) or (ID), may be a synthetically-produced compound or a metabolically-produced compound.

A suitable pharmaceutically acceptable pro-drug of a compound of the Formula (I), (IA), (IB), (IC) or (ID), is one that is based on reasonable medical judgement as being suitable for administration to the human or animal body without undesirable pharmacological activities and without undue toxicity.

Various forms of pro-drug have been described, for example in the following documents:—

-   -   a) Methods in Enzymology, Vol. 42, p. 309-396, edited by K.         Widder, et al. (Academic Press, 1985);     -   b) Design of Pro-drugs, edited by H. Bundgaard, (Elsevier,         1985);     -   c) A Textbook of Drug Design and Development, edited by         Krogsgaard-Larsen and H. Bundgaard, Chapter 5 “Design and         Application of Pro-drugs”, by H. Bundgaard p. 113-191 (1991);     -   d) H. Bundgaard, Advanced Drug Delivery Reviews, 8, 1-38 (1992);     -   e) H. Bundgaard, et al., Journal of Pharmaceutical Sciences, 77,         285 (1988);     -   f) N. Kakeya, et al., Chem. Pharm. Bull., 32, 692 (1984);     -   g) T. Higuchi and V. Stella, “Pro-Drugs as Novel Delivery         Systems”, A.C.S. Symposium Series, Volume 14; and     -   h) E. Roche (editor), “Bioreversible Carriers in Drug Design”,         Pergamon Press, 1987.

The in-vivo effects of a compound of the Formula (I), (IA), (IB), (IC) or (ID) may be exerted in part by one or more metabolites that are formed within the human or animal body after administration of a compound of the Formula (I), (IA), (IB), (IC) or (ID). As stated hereinbefore, the in-vivo effects of a compound of the Formula (I), (IA), (IB), (IC) or (ID), may also be exerted by way of metabolism of a precursor compound (a pro-drug).

For the avoidance of doubt it is to be understood that where in this specification a group is qualified by ‘hereinbefore defined’ or ‘defined herein’ the said group encompasses the first occurring and broadest definition as well as each and all of the alternative definitions for that group.

Another aspect of the present specification provides a process for preparing a compound of the Formula (I), (IA), (IB), (IC) or (ID), or a pharmaceutically acceptable salt thereof. A suitable process is illustrated by the following representative process variants in which, unless otherwise stated, A, D, E, G, Q and R¹ to R¹⁰ have any of the meanings defined hereinbefore. Necessary starting materials may be obtained by standard procedures of organic chemistry. The preparation of such starting materials is described in conjunction with the following representative process variants and within the accompanying Examples. Alternatively, necessary starting materials are obtainable by analogous procedures to those illustrated which are within the ordinary skill of an organic chemist.

Compounds of Formula (I), (IA), (IB), (IC) or (ID), may be made by, for example:

a) Reaction of a compound of formula (II) with a compound of formula (III) under conditions known in the art as suitable for Pictet-Spengler reactions (such as in the presence of acid (such as acetic acid) and in a suitable solvent (for example toluene) and a suitable temperature (such as 80-100° C.) with or without a protecting group (P) on the nitrogen that may be removed under conditions known to the art.

b) Where Q is O, by etherification of a suitable aryl halide of formula (IV), where L is for example a halogen (such as Br) or a trifluoromethanesulfonyl (triflate) group or a boronic acid or boronate ester, with an alcohol of formula (V) using a suitable metal catalyst (for example RockPhos 3rd Generation Precatalyst) in a suitable solvent (for example toluene or DME) in the presence of a suitable base (for example cesium carbonate) and a suitable temperature (such as 90-120° C.) with or without a protecting group (P) on the nitrogen that may be removed under conditions known to the art.

c) Where Q is O, by alkylation of a suitable phenol or hydroxyl heteroaryl compound of formula (VI) with an alcohol of formula (V) via Mitsunobu reaction using appropriate reagents (such as triphenylphosphine and diisopropyl (E)-diazene-1,2-dicarboxylate) in a suitable solvent (such as DCM) with or without a protecting group (P) on the nitrogen that may be removed under conditions known to the art.

d) Alkylation of a suitable compound of formula (VII), where LG is a leaving group known to the art, for example halide (such as Br), trifluoromethanesulfone (triflate) or methylsulfone (mesylate), with an amine of formula (VIII) in a suitable solvent (for example acetonitrile) in the presence of a suitable base (for example potassium carbonate) and a suitable temperature (such as 80-90° C.). with or without a protecting group (P) on the nitrogen that may be removed under conditions known to the art

Compounds of formula (II) may be prepared by, for example:

a) Reaction of a compound of formula (IX) with an aldehyde of formula (X), in a suitable solvent (for example THF) in the presence of a suitable reducing agent (such as sodium triacetoxyborohydride) and at a suitable temperature (such as 20-30° C.);

b) (i) reaction of a compound of formula (IX) with an acid of formula (XI) under standard amide bond forming conditions (for example in the presence of an amide coupling reagent (such as HATU) and a suitable base (such as triethylamine) in a suitable solvent (such as DMF)), followed by (ii) reduction of the resultant amide bond using a suitable reducing agent (such as borane) in a suitable solvent (such as THF) at a suitable temperature (such as 60-70° C.); c) reaction of a compound of formula (IX) with a compound of formula (XII), wherein LG is a suitable leaving group (for example a halogen atom (such as bromo or chloro) or trifluoromethanesulfone), in the presence of a suitable base (such as diisopropylethylamine) in a suitable solvent (for example DCM or dioxane) and at a suitable temperature (such as 20-85° C.).

Compounds of formula (III) may be prepared by reaction of a compound of formula (XIII) with an alcohol of formula (V) under conditions known in the art as suitable for Mitsunobu reactions (such as in the presence of an azodicarboxylate reagent (such as DEAD) and triphenylphosphine and in a suitable solvent (such as THF) and at a suitable temperature (such as 20-30° C.).

Compounds of formula (IV) may be prepared by reaction of a compound of formula (II) with a compound of formula (XIV), where L is a suitable functional group such as halide (for example bromide or chloride), triflate, boronic acid or boronic ester, under conditions known in the art as suitable for Pictet-Spengler reactions, such as in the presence of acid (such as acetic acid) and in a suitable solvent (for example toluene) and a suitable temperature (such as 80-100° C.).

Compounds of formula (VI) may be prepared by reaction of a compound of formula (II) with a compound of formula (XV), under conditions known in the art as suitable for Pictet-Spengler reactions (such as in the presence of acid (such as acetic acid) and in a suitable solvent (for example toluene) and a suitable temperature (such as 80-100° C.). In certain aspects X equals OH (optionally with a protecting group) or X equals a boronic acid or boronic ester that may be converted to an OH using a suitable oxidant (such as hydrogen peroxide) in the presence of a suitable base (such as sodium hydroxide) in a suitable solvent (such as THF).

Compounds of formula (VII) may be prepared by reaction of a compound of formula (VI) using standard functional group manipulations for example, a Mitsunobu reaction using appropriate reagents (such as triphenylphosphine and diisopropyl (E)-diazene-1,2-dicarboxylate) with 2-haloethanol (such as 2-bromoethan-1-ol) in a suitable solvent (such as DCM).

Alternatively, compounds of formula (VII) may be prepared by reaction of a compound of formula (IV) using standard functional group manipulations for example, an etherification, where L is for example a halogen (such as Br) or a trifluoromethanesulfonyl (triflate) group or a boronic acid or boronate ester, with an appropriate diol (with optional mono-protection) using a suitable metal catalyst (for example RockPhos 3rd Generation Precatalyst) in a suitable solvent (for example toluene or DME) in the presence of a suitable base (for example cesium carbonate). Subsequently, (with removal of protection if required) the alcohol may be converted into an appropriate leaving group (for example halide (such as Br), trifluoromethanesulfone (triflate) or methylsulfone (mesylate)) under standard conditions.

It is to be understood that other permutations of the process steps in the process variants described above are also possible.

When a pharmaceutically acceptable salt of a compound of Formula (I), (IA), (IB), (IC) or (ID), is required it may be obtained by, for example, reaction of said compound with a suitable acid or suitable base. When a pharmaceutically acceptable pro-drug of a compound of Formula (I), (IA), (IB), (IC) or (ID), is required, it may be obtained using a conventional procedure.

It will also be appreciated that, in some of the reactions mentioned hereinbefore, it may be necessary or desirable to protect any sensitive functionalities in the compounds. The instances where protection is necessary or desirable, and suitable methods for protection, are known to those skilled in the art. Conventional protecting groups may be used in accordance with standard practice (for illustration see T. W. Green, Protective Groups in Organic Synthesis, John Wiley and Sons, 1991). Thus, if reactants include groups such as amino, carboxy or hydroxy, it may be desirable to protect the group in some of the reactions mentioned herein.

A suitable protecting group for an amino or alkylamino group is, for example, an acyl group, for example an alkanoyl group such as acetyl, an alkoxycarbonyl group, for example a methoxycarbonyl, ethoxycarbonyl or t-butoxycarbonyl group, an arylmethoxycarbonyl group, for example benzyloxycarbonyl, or an aroyl group, for example benzoyl. The deprotection conditions for the above protecting groups necessarily vary with the choice of protecting group. Thus, for example, an acyl group such as an alkanoyl or alkoxycarbonyl group or an aroyl group may be removed for example, by hydrolysis with a suitable base such as an alkali metal hydroxide, for example lithium or sodium hydroxide. Alternatively an alkoxycarbonyl group such as a t-butoxycarbonyl group may be removed, for example, by treatment with a suitable acid as hydrochloric, sulphuric, formic, phosphoric or trifluoroacetic acid, and an arylmethoxycarbonyl group such as a benzyloxycarbonyl group may be removed, for example, by hydrogenation over a catalyst such as palladium-on-carbon, or by treatment with a Lewis acid, such as boron tris(trifluoroacetate). A suitable alternative protecting group for a primary amino group is, for example, a phthaloyl group, which may be removed by treatment with an alkylamine, for example dimethylaminopropylamine, or hydrazine.

A suitable protecting group for a hydroxy group is, for example, an acyl group, for example an alkanoyl group such as acetyl, an aroyl group, for example benzoyl, an arylmethyl group, for example benzyl, or a trialkyl or diarylalkyl silane, such as TBDMS or TBDPS. The deprotection conditions for the above protecting groups will necessarily vary with the choice of protecting group. Thus, for example, an acyl group such as an alkanoyl or an aroyl group may be removed, for example, by hydrolysis with a suitable base such as an alkali metal hydroxide, for example lithium or sodium hydroxide. Alternatively an arylmethyl group such as a benzyl group may be removed, for example, by hydrogenation over a catalyst such as palladium-on-carbon.

A suitable protecting group for a carboxy group is, for example, an esterifying group, for example a methyl or an ethyl group which may be removed, for example, by hydrolysis with a base such as sodium hydroxide, or for example a t-butyl group which may be removed, for example, by treatment with an acid, such as trifluoroacetic acid, or for example a benzyl group which may be removed, for example, by hydrogenation over a catalyst such as palladium-on-carbon.

The protecting groups may be removed at any convenient stage in the synthesis using conventional techniques well known in the chemical art.

Certain of the intermediates defined herein are novel and these are provided as further features of the specification.

Biological Assays

The following assays were used to measure the effects of the compounds of the present specification.

ERα Binding Assay

The ability of compounds to bind to isolated Estrogen Receptor Alpha Ligand binding domain (ER alpha-LBD (GST)) was assessed in competition assays using a LanthaScreen™ Time-Resolved Fluorescence Resonance Energy Transfer (TR-FRET) detection end-point. For the LanthaScreen TR-FRET endpoint, a suitable fluorophore (Fluormone ES2, ThermoFisher, Product code P2645) and recombinant human Estrogen Receptor alpha ligand binding domain, residues 307-554 (expressed and purified in-house) were used to measure compound binding. The assay principle is that ER alpha-LBD (GST) is added to a fluorescent ligand to form a receptor/fluorophore complex. A terbium-labelled anti-GST antibody (Product code PV3551) is used to indirectly label the receptor by binding to its GST tag, and competitive binding is detected by a test compound's ability to displace the fluorescent ligand, resulting in a loss of TR-FRET signal between the Tb-anti-GST antibody and the tracer. The assay was performed as follows with all reagent additions carried out using the Beckman Coulter BioRAPTR FRD microfluidic workstation:

-   -   1. Acoustic dispense 120 nL of the test compound into a black         low volume 384 well assay plates.     -   2. Prepare 1×ER alpha-LBD/Tb-antiGST Ab in ES2 screening buffer         and incubate for 15 minutes.     -   3. Dispense 6 μL of the 1×AR-LBD/Tb-anti-GST Ab reagent into         each well of the assay plate followed by 6 μL of Fluorophore         reagent into each well of the assay plate     -   4. Cover the assay plate to protect the reagents from light and         evaporation, and incubate at room temperature for 4 hours.     -   5. Excite at 337 nm and measure the fluorescent emission signal         of each well at 490 nm and 520 nm using the BMG PheraSTAR.

Compounds were dosed directly from a compound source microplate containing serially diluted compound (4 wells containing 10 mM, 0.1 mM, 1 mM and 10 nM final compound respectively) to an assay microplate using the Labcyte Echo 550. The Echo 550 is a liquid handler that uses acoustic technology to perform direct microplate-to-microplate transfers of DMSO compound solutions and the system can be programmed to transfer multiple small nL volumes of compound from the different source plate wells to give the desired serial dilution of compound in the assay which is then back-filled to normalise the DMSO concentration across the dilution range.

In total 120 nL of compound plus DMSO were added to each well and compounds were tested in a 12-point concentration response format over a final compound concentration range of 10, 2.917, 1.042, 0.2083, 0.1, 0.0292, 0.0104, 0.002083, 0.001, 0.0002917, 0.0001042, and 0.00001 μM respectively. TR-FRET dose response data obtained with each compound was exported into a suitable software package (such as Origin or Genedata) to perform curve fitting analysis. Competitive ER alpha binding was expressed as an IC₅₀ value. This was determined by calculation of the concentration of compound that was required to give a 50% reduction in tracer compound binding to ER alpha-LBD.

MCF-7 ER Down-Regulation Assay

The ability of compounds to down-regulate Estrogen Receptor (ER) numbers was assessed in a cell based immuno-fluorescence assay using the MCF-7 human ductal carcinoma breast cell line. MCF-7 cells were revived directly from a cryovial (approx 5×10⁶ cells) in Assay Medium (phenol red free Dulbecco's Modified Eagle's medium (DMEM); Sigma D5921) containing 2 mM L-Glutamine and 5% (v/v) Charcoal/Dextran treated foetal calf serum. Cells were syringed once using a sterile 18 G×1.5 inch (1.2×40 mm) broad gauge needle and cell density was measured using a Coulter Counter (Beckman). Cells were further diluted in Assay Medium to a density of 3.75×10⁴ cells per mL and 40 μL per well added to transparent bottomed, black, tissue culture-treated 384 well plates (Costar, No. 3712) using a Thermo Scientific Matrix WellMate or Thermo Multidrop. Following cell seeding, plates were incubated overnight at 37° C., 5% CO₂ (Liconic carousel incubator). Test data was generated using the LabCyte Echo™ model 555 compound reformatter which is part of an automated workcell (Integrated Echo 2 workcell). Compound stock solutions (10 mM) of the test compounds were used to generate a 384 well compound dosing plate (Labcyte P-05525-CV1). 40 μL of each of the 10 mM compound stock solutions was dispensed into the first quadrant well and then 1:100 step-wise serial dilutions in DMSO were performed using a Hydra II (MATRIX UK) liquid handling unit to give 40 μL of diluted compound into quadrant wells 2 (0.1 mM), 3 (1 μM) and 4 (0.01 μM), respectively. 40 μL of DMSO added to wells in row P on the source plate allowed for DMSO normalisation across the dose range. To dose the control wells 40 μL of DMSO was added to row O1 and 40 μL of 100 μM fulvestrant in DMSO was added to row O3 on the compound source plate.

The Echo uses acoustic technology to perform direct microplate-to-microplate transfers of DMSO compound solutions to assay plates. The system can be programmed to transfer volumes as low as 2.5 nL in multiple increments between microplates and in so doing generates a serial dilution of compound in the assay plate which is then back-filled to normalise the DMSO concentration across the dilution range. Compounds were dispensed onto the cell plates with a compound source plate prepared as above producing a 12 point duplicate 3 μM to 3 pM dose range with 3-fold dilutions and one final 10-fold dilution using the Integrated Echo 2 workcell. The maximum signal control wells were dosed with DMSO to give a final concentration of 0.3%, and the minimum signal control wells were dosed with fulvestrant to give a final concentration of 100 nM accordingly. Plates were further incubated for 18-22 hours at 37° C., 5% CO₂ and then fixed by the addition of 20 μL of 11.1% (v/v) formaldehyde solution (in phosphate buffered saline (PBS)) giving a final formaldehyde concentration of 3.7% (v/v). Cells were fixed at room temperature for 20 mins before being washed two times with 250 μL PBS/Proclin (PBS with a Biocide preservative) using a BioTek platewasher, 40 μL of PBS/Proclin was then added to all wells and the plates stored at 4° C. The fixing method described above was carried out on the Integrated Echo 2 workcell. Immunostaining was performed using an automated AutoElisa workcell. The PBS/Proclin was aspirated from all wells and the cells permeabilized with 40 μL PBS containing 0.5% Tween™ 20 (v/v) for 1 hour at room temperature. The plates were washed three times in 250 μL of PBS/0.05% (v/v) Tween 20 with Proclin (PBST with a Biocide preservative) and then 20 μL of ERα (SP1) Rabbit monoclonal antibody (Thermofisher) 1:1000 in PBS/Tween™/3% (w/v) Bovine Serum Albumin was added. The plates were incubated overnight at 4° C. (Liconic carousel incubator) and then washed three times in 250 μL of PBS/0.05% (v/v) Tween™ 20 with Proclin (PBST). The plates were then incubated with 20 μL/well of a goat anti-rabbit IgG AlexaFluor 594 or goat anti-rabbit AlexaFluor 488 antibody (Molecular Probes) with Hoechst at 1:5000 in PBS/Tween™/3% (w/v) Bovine Serum Albumin for 1 hour at room temperature. The plates were then washed three times in 250 μL of PBS/0.05% (v/v) Tween™ 20 with Proclin (PBST with a Biocide preservative). 20 μL of PBS was added to each well and the plates covered with a black plate seal and stored at 4° C. before being read. Plates were read using a Cellomics Arrayscan reading the 594 nm (24 hr time point) or 488 nm (5 hr timepoint) fluorescence to measure the ERα receptor level in each well. The mean total intensity was normalized for cell number giving the total intensity per cell. The data was exported into a suitable software package (such as Origin) to perform curve fitting analysis. Down-regulation of the ERα receptor was expressed as an IC₅₀ value and was determined by calculation of the concentration of compound that was required to give a 50% reduction of the average maximum Total Intensity signal.

The data shown in Table A were generated (the data below may be a result from a single experiment or an average of two or more experiments):

TABLE A ER binding IC₅₀ ER down regulation Example value (nM) IC₅₀ value (nM)¹ 1 6.6 0.94 2 4.3 0.43 3 1.1 0.14 4 0.2 0.08 5 1.1 0.49 6 1.3 0.26 7 2.1 0.51 8 1.2 0.16 9 4.8 0.22 10 1.1 0.12 11 4.7 0.46 12 0.91 0.19 13 2.4 0.42 14 2.5 0.64 (89%) 15 1.7 0.37 16 2.5 0.5 17 1.4 0.086 (85%) 18 2.3 0.65 (85%) 19 2.5 0.41 (68%) 20 1.8 0.26 21 4.8 0.48 22 1.1 0.81 23 6.7 0.59 (89%) 24 4.9 0.79 25 2.2 0.36 26 1.2 0.38 27 2.2 1.5 (79%) 28 6.2 11 (48%) 29 9 19 (57%) 30 1.3 1.2 31 12 22 (89%) 32 37 41 33 2.5 3.3 (87%) 34 3.2 6.2 35 1.8 0.28 36 2.3 0.14 37 2.4 0.51 38 1.9 0.43 39 11 230 40 1.7 0.17 41 1.5 0.14 42 1.2 0.079 43 1.8 0.15 44 2.5 0.17 45 4.3 0.31 46 1.2 0.093 47 27 0.24 48 1.5 0.26 49 2.1 0.25 50 2.3 0.087 51 3.5 0.78 (78%) 52 2.2 0.24 (79%) 53 2.8 0.14 54 1.6 0.13 55 1.6 0.2 (89%) 56 2 0.4 57 3.3 0.27 58 1.6 0.087 59 9.9 0.25 60 14 1.8 61 4.3 0.24 62 10 3.9 63 3.1 1.8 64 1.2 0.21 65 2.4 0.63 (87%) 66 5.3 1.0 67 2.5 0.87 68 2.6 0.33 69 0.97 0.54 70 1.2 0.88 71 1.0 0.83 72 2.4 0.47 (87%) 73 2.7 0.094 74 2.0 0.14 75 4.5 1.2 76 3.0 0.32 77 2.1 0.71 (85%) 78 7.6 0.21 ¹Compounds tested in the ER down regulation assay show downregulation values (>90%) in the assay unless otherwise stated, in which case the % downregulation is shown in brackets. (NT = not tested). Western Blotting Assay

The ability of compounds to down-regulate estrogen receptor (ER) was assessed by western blotting using human breast cancer cell lines (MCF-7 and CAMA-1). Cells were plated into 12-well tissue culture-treated plates at 0.5×10⁶/well in phenol red-free RPMI containing 2 mM L-glutamine and 5% (v/v) charcoal treated foetal calf serum (F6765, Sigma). Cells were incubated with compounds (100 nM) or vehicle control (0.1% DMSO) for 48 h at 37° C., 5% CO₂ before washing once with PBS and lysing with 80 μl lysis buffer (25 mM Tris/HCl, 3 mM EDTA, 3 mM EGTA, 50 mM NaF, 2 mM sodium orthovanadate, 0.27 M sucrose, 10 mM β-glycerophosphate, 5 mM sodium pyrophosphate, 0.5% TritonX-100, pH 6.8) on ice.

Cells were scraped, sonicated and centrifuged prior to performing a protein assay (DC Bio-Rad Protein kit, 500-0116) and making samples to a protein concentration of 1-2 mg/ml in lysis buffer containing 1×LDS Sample Buffer (NP0007, Invitrogen) and 1× NuPAGE sample reducing agent (NP0009, Invitrogen). Samples were boiled for 10 min at 95° C. and then frozen at −20° C. until ready for use.

10-20 μg protein was loaded onto 26-well Criterion gels (BioRad 345-0034). Gels were run at 125 V for 1 hr 25 min in running buffer (24 mM Tris Base Sigma, 192 mM Glycine, 3.5 mM SDS, made up in distilled water). Gels were then transferred at 30V for 2 hr in transfer buffer (25 mM Tris, 192 mM Glycine, 20% (v/v) methanol, pH 8.3, made up in distilled water) onto nitrocellulose membrane. The blot was stained with Ponceau S (P7170, Sigma) and cut according to appropriate molecular weight markers.

Membranes were blocked for 1 hour at room temp in 5% Marvel (w/v) in phosphate-buffered saline containing 0.05% Tween™ 20 (PBS/Tween). Blots were then incubated with anti-ERα (SP1) rabbit monoclonal antibody (Thermofisher) diluted 1:1000 at 4° C. overnight (with gentle shaking) followed by several washes with PBS/Tween. Secondary anti-rabbit HRP antibody (7074, CST) diluted 1:2000 dilution was incubated for 2 h at room temperature (with gentle shaking) followed by several washes with PBS/Tween. All antibodies were made up in 5% Marvel (w/v) in PBS/Tween.

The immunoblots were developed using Pierce WestDura chemiluminescent reagents (Thermo Scientific 34076) and developed/quantified on the G-box using Syngene software. Down-regulation of the ERα receptor was normalised to the vehicle control (0% down-regulation) and the 100 nM fulvestrant control (100% down-regulation) run within the same gel.

Table B shows the data generated for selected Examples (the data below may be a result from a single experiment or an average of two or more experiments):

TABLE B CAMA1 Western MCF7 Western Example % ER deg vs Fv % ER deg vs Fv 3 0 64 4 45 51 5 51 65 6 47 74 7 48 74 8 38 77 9 80 82 10 73 71 11 54 81 12 55 87 13 82 82 14 31 61 35 82 81 36 66 83 38 75 88 40 85 90 41 89 74 42 76 90 43 65 88 44 90 85 45 72 97 46 74 88 47 81 90 48 65 58 49 95 100 54 92 87 56 66 74 58 58 86 64 87 73 75 60 31 Human Hepatocyte Assay

The metabolic stability of compounds in human hepatocytes was assessed using the following protocol:

-   -   1. Prepare 10 mM stock solutions of compound and control         compounds in appropriate solvent (DMSO). Place incubation medium         (L-15Medium) in a 37° C. water bath, and allow warming for at         least 15 minutes prior to use.     -   2. Add 80 μL of acetonitrile to each well of the 96-well deep         well plate (quenching plate).     -   3. In a new 96-well plate, dilute the 10 mM test compounds and         the control compounds to 100 μM by combining 198 μL of         acetonitrile and 2 μL of 10 mM stock.     -   4. Remove a vial of cryopreserved (less than −150° C.) human         hepatocytes (LiverPool™ 10 Donor Human hepatocytes obtained from         Celsis IVT. Chicago, Ill. (Product No. S01205)) from storage,         ensuring that vials remain at cryogenic temperatures until         thawing process ensues. As quickly as possible, thaw the cells         by placing the vial in a 37° C. water bath and gently shaking         the vials. Vials should remain in water bath until all ice         crystals have dissolved and are no longer visible. After thawing         is complete, spray vial with 70% ethanol, transfer the vial to a         bio-safety cabinet.     -   5. Open the vial and pour the contents into the 50 mL conical         tube containing thawing medium. Place the 50 mL conical tube         into a centrifuge and spin at 100 g for 10 minutes. Upon         completion of spin, aspirate thawing medium and resuspend         hepatocytes in enough incubation medium to yield ˜1.5×10⁶         cells/mL.     -   6. Using Cellometer® Vision, count cells and determine the         viable cell density. Cells with poor viability (<80% viability)         are not acceptable for use. Dilute cells with incubation medium         to a working cell density of 1.0×10⁶ viable cells/mL.     -   7. Transfer 247.5 μL of hepatocytes into each well of a 96-well         cell culture plate. Place the plate on Eppendorf Thermomixer         Comfort plate shaker to allow the hepatocytes to warm for 10         minutes.     -   8. Add 2.5 μL of 100 μM test compound or control compounds into         an incubation well containing cells, mix to achieve a homogenous         suspension at 0.5 min, which when achieved, will define the 0.5         min time point. At the 0.5 min time, transfer 20 μL of incubated         mixture to wells in a “Quenching plate” followed by vortexing.     -   9. Incubate the plate at 37° C. at 900 rpm on an Eppendorf         Thermomixer Comfort plate shaker. At 5, 15, 30, 45, 60, 80, 100         and 120 min, mix the incubation system and transfer samples of         20 μL incubated mixture at each time point to wells in a         separate “Quenching plate” followed by vortexing.     -   10. Centrifuge the quenching plates for 20 minutes at 4,000 rpm.         4 different compounds are pooled into one cassette and used for         LC/MS/MS analysis.

All calculations were carried out using Microsoft Excel. Peak areas were determined from extracted ion chromatograms. In vitro intrinsic clearance (in vitro Cl_(int), in L/min/10⁶ cells) of parent compound was determined by regression analysis of the Ln percent parent disappearance vs. time curve. The in vitro intrinsic clearance (in vitro Cl_(int), in L/min/10⁶ cells) was determined from the slope value using the following equation and is shown in Table C: in vitro Cl _(int) =kV/N

V=incubation volume (0.25 mL);

N=number of hepatocytes per well (0.25×10⁶ cells).

TABLE C Cl_(int) Example (μL/min/10⁶ cells) 1 <1 2 <1 3 NT 4 2 5 2 6 <1 30 5 40 5 (NT = not tested) Physical Properties Log D

The lipophilicity of a drug is an important physical property which may influence many biological and metabolic properties of a compound, for example the absorption, distribution, metabolism, excretion and toxicity profiles of a compound. The distribution coefficient between 1-octanol and aqueous buffer, Log DO/W, at pH 7.4, is the most commonly used measurement of the lipophilicity of a compound. The current method for measurement of Log DO/W is based on the traditional shake flask technique, but with the modification of measuring compounds in mixtures of ten at a time using UPLC with quantitative mass spectrometry (MS) as a method to measure the relative octanol and aqueous concentrations. The maximum capacity is 379 project compounds (48 pools with 10 compounds incl. three QC compounds) per experiment. 2 quality control (QC) samples, Cyclobenzaprine with moderate Log D and Nicardipine high Log D is used in all pools to ensure good quality. An additional QC sample Caffeine, with low Log D, are used and randomly placed in all runs. The method has been thoroughly validated against the previous shake flask methodologies.

Solubility

In order for an oral compound to reach the site of action, and in order for oral absorption from the gut to occur, that compound must be in solution, and therefore compounds which possess high intrinsic solubility may be more suitable for pharmaceutical use. The thermodynamic solubility of a research compound is measured under standard conditions. It is a shake-flask approach that uses 10 mM DMSO solutions which are supplied from the Compound Managements liquid store and is a high throughput method. The dried compounds are equilibrated in an aqueous phosphate buffer (pH 7.4) for 24 hours at 25° C., the portion with the dissolved compound is then separated from the remains. The solutions are analyzed and quantified using UPLC/MS/MS, QC-samples are incorporated in each assay-run to ensure the quality of the assay.

Human Plasma Protein Binding

Hunan plasma protein binding is a key factor in controlling the amount of free (unbound) drug available for binding to target and hence plays an important role in the observed efficacy of drugs in vivo. Therefore, compounds which possess high free fraction (low levels of plasma protein binding) may exhibit enhanced efficacy relative to a compound with similar potency and exposure levels. The automated equilibrium dialysis assay in human plasma uses the RED (Rapid Equilibrium Dialysis) Device and sample handling. The assay generally runs over two to three days including delivery of results. After dialysis for 18 hours, plasma and buffer samples are prepared for analysis by liquid chromatography and mass spectrometry. Samples are generally tested in singlicates and quantified by LC/MSMS by using a 7-point calibration curve in plasma. The compounds are pooled together in plasma pools up to 10 compounds. Three reference compounds are used in each run, Propranolol, Metoprolol and Warfarin. Warfarin is used as a control in each pool and Propranolol and Metoprolol are placed randomly in each run. An in-house Excel macro is used for preparation of files for the robot and the mass spectrometer and is also used for the calculations of fraction unbound (fu %) in plasma.

Table D shows the data for log D, solubility, plasma protein binding and permeability generated for selected Examples (the data below may be a result from a single experiment or an average of two or more experiments):

TABLE D Human plasma LogD Solubility protein binding Example pH 7.4 (μM) (% free) 1 4.6 34 1.4 2 3.6 301 1.5 3 >4.3 4 <2.6 4 >4.0 20 <0.34 5 2.9 340 3.9 6 3.4 165 1.3 7 2.3 >1000 17 8 2.8 319 6.1 9 3.7 543 0.95 10 2.9 592 3.2 11 3.2 642 4.5 12 4.1 12 0.61 13 3.4 150 1.6 14 3.6 10 0.9 15 3.4 83 1.5 16 3.1 149 1.8 17 2.6 629 3.9 18 2.7 639 2.4 19 >4.4 11 0.56 20 >3.9 18 <0.30 21 3.4 149 2.1 22 3.0 197 6.1 23 3.3 122 1.7 24 2.7 370 4.7 25 3.0 135 1.6 26 3.2 65 2.7 27 3.0 281 5.2 28 2.9 354 2.7 30 3.4 135 2.0 31 2.7 554 5.3 32 2.1 980 16 33 3.0 244 3.0 34 2.5 787 11 35 3.8 99 2.2 36 3.5 291 2.1 37 2.4 877 8.5 38 3.3 227 1.3 39 2.5 328 7.2 40 2.7 854 5.8 41 3.2 389 2.4 42 3.3 220 1.6 43 3.3 163 1.5 44 3.1 577 2.3 45 3.5 85 1.0 46 2.6 952 2.3 47 2.5 840 5.0 48 3.4 94 — 49 — 70 0.40 50 3.9 47 0.61 51 3.8 53 0.41 52 >4.1 14 0.47 53 >4.2 23 0.55 54 — 242 1.3 55 4.1 32 — 56 3.3 184 — 57 4.0 35 0.41 58 2.8 418 4.0 59 2.9 853 2.8 60 2.9 760 7.8 61 3.4 24 1.3 62 2.7 587 13 63 >3.6 268 1.4 64 2.2 849 12 65 2.1 911 14 66 2.0 >1000 20 67 2.5 >1000 — 68 3.1 438 — 69 2.0 820 15 70 2.4 607 11 71 2.3 >1000 13 72 3.4 96 2.3 73 >3.2 51 0.66 74 3.9 30 0.33 75 3.4 411 1.0 76 3.0 335 — 77 >3.6 108 0.19 78 4.0 192 — Human Caco-2 Bidirectional Permeability A to B and B to A

An automated assay was used to determine the bidirectional permeability (efflux and uptake) of compounds in Caco-2 cells carried out over 2 hours at pH 7.4. Samples were analyzed through LC/MS/MS to estimate the apparent permeability coefficients (Papp) of compounds across Caco-2 cell monolayers and results are quoted in units of ×10⁻⁶ cm/s.

The efflux ratio (ER) can be determined using the following equation: ER=P _(app(B-A)) /P _(app(A-B))

Where P_(app (B-A)) indicates the apparent permeability coefficient in basolateral to apical direction, and P_(app (A-B)) indicates the apparent permeability coefficient in apical to basolateral direction.

Human Caco-2 Passive Permeability A to B Papp

An automated assay was used to determine the passive permeability of compounds in Caco-2 cell monolayers carried out over 2 hours with an apical pH of 6.5 and basolateral pH of 7.4. The Caco-2 AB inhibition assay is carried out with chemical inhibition of the three major efflux transporters ABCB1 (P-gp), ABCG2 (BCRP) and ABCC2 (MRP2) in Caco-2 cells. Incubation of both apical and basolateral is carried out with a cocktail of inhibitors (50 μM quinidine, 20 μM sulfasalazine and 100 μM benzbromarone). Samples were analyzed through LC/MS/MS to estimate the apparent permeability coefficients (Papp) of compounds across Caco-2 cell monolayers and results are quoted in units of ×10⁻⁶ cm/s.

Table E shows the data for permeability generated for selected Examples (the data below may be a result from a single experiment or an average of two or more experiments):

TABLE E Bidirectional Bidirectional Passive Caco-2 Papp Caco-2 Caco-2 Papp Example (×10⁻⁶ cm/s) efflux ratio (×10⁻⁶ cm/s) 4 0.027 35 — 5 2.0 1.8 11 6 0.62 5.2  9 8 0.84 3.4 — 9 0.3 3.2 — 10 1.6 1.6 — 11 0.27 4.2 — 40 3.2 1.8 14

According to a further aspect of the specification there is provided a pharmaceutical composition, which comprises a compound of the Formula (I), (IA), (IB), (IC) or (ID), or a pharmaceutically acceptable salt thereof, as defined hereinbefore in association with a pharmaceutically acceptable excipient.

Suitable pharmaceutically acceptable excipients for a tablet formulation include, for example, inert diluents, granulating and disintegrating agents, binding agents, lubricating agents, preservative agents and antioxidants. A further suitable pharmaceutically acceptable excipient may be a chelating agent. Tablet formulations may be uncoated or coated either to modify their disintegration and the subsequent absorption of the active ingredient within the gastrointestinal tract, or to improve their stability and/or appearance, in either case, using conventional coating agents and procedures well known in the art.

Compositions for oral use may alternatively be in the form of hard gelatin capsules in which the active ingredient is mixed with an inert solid diluent, or as soft gelatin capsules in which the active ingredient is mixed with water or an oil.

Aqueous suspensions generally contain the active ingredient in finely powdered form together with one or more suspending agents, dispersing or wetting agents. The aqueous suspensions may also contain one or more preservatives, anti-oxidants, colouring agents, flavouring agents, and/or sweetening agents.

Oily suspensions may be formulated by suspending the active ingredient in a vegetable oil or in a mineral oil. The oily suspensions may also contain a thickening agent. Sweetening agents such as those set out above, and flavouring agents may be added to provide a palatable oral preparation. These compositions may be preserved by the addition of an anti-oxidant.

Dispersible powders and granules suitable for preparation of an aqueous suspension by the addition of water generally contain the active ingredient together with a dispersing or wetting agent, suspending agent and one or more preservatives. Additional excipients such as sweetening, flavouring and colouring agents, may also be present.

The pharmaceutical compositions of the specification may also be in the form of oil-in-water emulsions. The oily phase may be a vegetable oil or a mineral oil or a mixture of any of these. The emulsions may also contain sweetening, flavouring and preservative agents.

Syrups and elixirs may be formulated with sweetening agents, and may also contain a demulcent, preservative, flavouring and/or colouring agent.

The pharmaceutical compositions may also be in the form of a sterile injectable aqueous or oily suspension, which may be formulated according to known procedures using one or more of the appropriate dispersing or wetting agents and suspending agents, which have been mentioned above. A sterile injectable preparation may also be a sterile injectable solution or suspension in a non-toxic parenterally-acceptable diluent or solvent system.

Compositions for administration by inhalation may be in the form of a conventional pressurised aerosol arranged to dispense the active ingredient either as an aerosol containing finely divided solid or liquid droplets. Conventional aerosol propellants such as volatile fluorinated hydrocarbons or hydrocarbons may be used and the aerosol device is conveniently arranged to dispense a metered quantity of active ingredient. Dry powder inhalers may also be suitable.

For further information on formulation the reader is referred to Chapter 25.2 in Volume 5 of Comprehensive Medicinal Chemistry (Corwin Hansch; Chairman of Editorial Board), Pergamon Press 1990.

The amount of active ingredient that is combined with one or more excipients to produce a single dosage form will necessarily vary depending upon the host treated and the particular route of administration. For example, oral administration to humans will generally require, for example, from 1 mg to 2 g of active agent (more suitably from 100 mg to 2 g, for example from 250 mg to 1.8 g, such as from 500 mg to 1.8 g, particularly from 500 mg to 1.5 g, conveniently from 500 mg to 1 g) to be administered compounded with an appropriate and convenient amount of excipients which may vary from about 3 to about 98 percent by weight of the total composition. It will be understood that, if a large dosage is required, multiple dosage forms may be required, for example two or more tablets or capsules, with the dose of active ingredient divided conveniently between them. Typically, unit dosage forms will contain about 10 mg to 0.5 g of a compound of this specification, although a unit dosage form may contain up to 1 g. Conveniently, a single solid dosage form may contain between 1 and 300 mg of active ingredient.

The size of the dose for therapeutic or prophylactic purposes of compounds of the present specification will naturally vary according to the nature and severity of the disease state, the age and sex of the animal or patient and the route of administration, according to well-known principles of medicine.

In using compounds of the present specification for therapeutic or prophylactic purposes it will generally be administered so that a daily dose in the range, for example, 1 mg/kg to 100 mg/kg body weight is received, given if required in divided doses. In general, lower doses will be administered when a parenteral route is employed. Thus, for example, for intravenous administration, a dose in the range, for example, 1 mg/kg to 25 mg/kg body weight will generally be used. Similarly, for administration by inhalation, a dose in the range, for example, 1 mg/kg to 25 mg/kg body weight will be used. Oral administration is however preferred, particularly in tablet form.

In one aspect of the specification, compounds of the present specification or pharmaceutically acceptable salts thereof, are administered as tablets comprising 10 mg to 100 mg of the compound of the specification (or a pharmaceutically acceptable salt thereof), wherein one or more tablets are administered as required to achieve the desired dose.

As stated above, it is known that signalling through ERα causes tumorigenesis by one or more of the effects of mediating proliferation of cancer and other cells, mediating angiogenic events and mediating the motility, migration and invasiveness of cancer cells. We have found that the compounds of the present specification possess potent anti-tumour activity which it is believed is obtained by way of antagonism and down-regulation of ERα that is involved in the signal transduction steps which lead to the proliferation and survival of tumour cells and the invasiveness and migratory ability of metastasising tumour cells.

Accordingly, the compounds of the present specification may be of value as anti-tumour agents, in particular as selective inhibitors of the proliferation, survival, motility, dissemination and invasiveness of mammalian cancer cells leading to inhibition of tumour growth and survival and to inhibition of metastatic tumour growth. Particularly, the compounds of the present specification may be of value as anti-proliferative and anti-invasive agents in the containment and/or treatment of solid tumour disease. Particularly, the compounds of the present specification may be useful in the prevention or treatment of those tumours which are sensitive to inhibition of ERα and that are involved in the signal transduction steps which lead to the proliferation and survival of tumour cells and the migratory ability and invasiveness of metastasising tumour cells. Further, the compounds of the present specification may be useful in the prevention or treatment of those tumours which are mediated alone or in part by antagonism and down-regulation of ERα, i.e. the compounds may be used to produce an ERα inhibitory effect in a warm-blooded animal in need of such treatment.

According to a further aspect of the specification there is provided a compound of the Formula (I), (IA), (IB), (IC) or (ID), or a pharmaceutically acceptable salt thereof, as defined hereinbefore for use as a medicament in a warm-blooded animal such as man.

According to a further aspect of the specification, there is provided a compound of the Formula (I), (IA), (IB), (IC) or (ID), or a pharmaceutically acceptable salt thereof, as defined hereinbefore for use in the production of an anti-proliferative effect in a warm-blooded animal such as man.

According to a further aspect of the specification there is provided a compound of the Formula (I), (IA), (IB), (IC) or (ID), or a pharmaceutically acceptable salt thereof, as defined hereinbefore for use in a warm-blooded animal such as man as an anti-invasive agent in the containment and/or treatment of solid tumour disease.

According to a further aspect of the specification, there is provided the use of a compound of the Formula (I), (IA), (IB), (IC) or (ID), or a pharmaceutically acceptable salt thereof, as defined hereinbefore, for the production of an anti-proliferative effect in a warm-blooded animal such as man.

According to a further aspect of the specification there is provided the use of a compound of the Formula (I), (IA), (IB), (IC) or (ID), or a pharmaceutically acceptable salt thereof, as defined hereinbefore, in the manufacture of a medicament for use in the production of an anti-proliferative effect in a warm-blooded animal such as man.

According to a further aspect of the specification there is provided the use of a compound of the Formula (I), (IA), (IB), (IC) or (ID), or a pharmaceutically acceptable salt thereof, as defined hereinbefore, in the manufacture of a medicament for use in a warm-blooded animal such as man as an anti-invasive agent in the containment and/or treatment of solid tumour disease.

According to a further aspect of the specification there is provided a method for producing an anti-proliferative effect in a warm-blooded animal, such as man, in need of such treatment which comprises administering to said animal an effective amount of a compound of the Formula (I), (IA), (IB), (IC) or (ID), or a pharmaceutically acceptable salt thereof, as defined hereinbefore.

According to a further aspect of the specification there is provided a method for producing an anti-invasive effect by the containment and/or treatment of solid tumour disease in a warm-blooded animal, such as man, in need of such treatment which comprises administering to said animal an effective amount of a compound of the Formula (I), (IA), (IB), (IC) or (ID), or a pharmaceutically acceptable salt thereof, as defined hereinbefore.

According to a further aspect of the specification, there is provided a compound of the Formula (I), (IA), (IB), (IC) or (ID), or a pharmaceutically acceptable salt thereof, as defined hereinbefore, for use in the prevention or treatment of cancer in a warm-blooded animal such as man.

According to a further aspect of the specification there is provided the use of a compound of the Formula (I), (IA), (IB), (IC) or (ID), or a pharmaceutically acceptable salt thereof, as defined hereinbefore in the manufacture of a medicament for use in the prevention or treatment of cancer in a warm-blooded animal such as man.

According to a further aspect of the specification there is provided a method for the prevention or treatment of cancer in a warm-blooded animal, such as man, in need of such treatment which comprises administering to said animal an effective amount of a compound of the Formula (I), (IA), (IB), (IC) or (ID), or a pharmaceutically acceptable salt thereof, as defined hereinbefore.

According to a further aspect of the specification, there is provided a compound of the Formula (I), (IA), (IB), (IC) or (ID), or a pharmaceutically acceptable salt thereof, as defined hereinbefore for use in the prevention or treatment of solid tumour disease in a warm-blooded animal such as man.

According to a further aspect of the specification there is provided the use of a compound of the Formula (I), (IA), (IB), (IC) or (ID), or a pharmaceutically acceptable salt thereof, as defined hereinbefore, in the manufacture of a medicament for use in the prevention or treatment of solid tumour disease in a warm-blooded animal such as man.

According to a further aspect of the specification there is provided a method for the prevention or treatment of solid tumour disease in a warm-blooded animal, such as man, in need of such treatment which comprises administering to said animal an effective amount of a compound of the Formula (I), (IA), (IB), (IC) or (ID), or a pharmaceutically acceptable salt thereof, as defined hereinbefore.

According to a further aspect of the specification there is provided a compound of the Formula (I), (IA), (IB), (IC) or (ID), or a pharmaceutically acceptable salt thereof, as defined hereinbefore, for use in the prevention or treatment of those tumours which are sensitive to inhibition of ERα that are involved in the signal transduction steps which lead to the proliferation, survival, invasiveness and migratory ability of tumour cells.

According to a further aspect of the specification there is provided the use of a compound of the Formula (I), (IA), (IB), (IC) or (ID), or a pharmaceutically acceptable salt thereof, as defined hereinbefore, in the manufacture of a medicament for use in the prevention or treatment of those tumours which are sensitive to inhibition of ERα that are involved in the signal transduction steps which lead to the proliferation, survival, invasiveness and migratory ability of tumour cells.

According to a further aspect of the specification there is provided a method for the prevention or treatment of those tumours which are sensitive to inhibition of ERα that are involved in the signal transduction steps which lead to the proliferation, survival, invasiveness and migratory ability of tumour cells which comprises administering to said animal an effective amount of a compound of the Formula (I), (IA), (IB), (IC) or (ID), or a pharmaceutically acceptable salt thereof, as defined hereinbefore.

According to a further aspect of the specification there is provided a compound of the Formula (I), (IA), (IB), (IC) or (ID), or a pharmaceutically acceptable salt thereof, as defined hereinbefore for use in providing an inhibitory effect on ERα.

According to a further aspect of the specification there is provided the use of a compound of the Formula (I), (IA), (IB), (IC) or (ID), or a pharmaceutically acceptable salt thereof, as defined hereinbefore in the manufacture of a medicament for use in providing an inhibitory effect on ERα.

According to a further aspect of the specification there is also provided a method for providing an inhibitory effect on ERα which comprises administering an effective amount of a compound of the Formula (I), (IA), (IB), (IC) or (ID), or a pharmaceutically acceptable salt thereof, as defined hereinbefore.

According to a further aspect of the specification there is provided a compound of the Formula (I), (IA), (IB), (IC) or (ID), or a pharmaceutically acceptable salt thereof, as defined hereinbefore, for use in providing a selective inhibitory effect on ERα.

According to a further aspect of the specification there is provided the use of a compound of the Formula (I), (IA), (IB), (IC) or (ID), or a pharmaceutically acceptable salt thereof, as defined hereinbefore, in the manufacture of a medicament for use in providing a selective inhibitory effect on ERα.

According to a further aspect of the specification there is also provided a method for providing a selective inhibitory effect on ERα which comprises administering an effective amount of a compound of the Formula (I), (IA), (IB), (IC) or (ID), or a pharmaceutically acceptable salt thereof, as defined hereinbefore.

Described herein are compounds that can bind to ERα ligand binding domain and are selective estrogen receptor degraders. In biochemical and cell based assays the compounds of the present specification are shown to be potent estrogen receptor binders and reduce cellular levels of ERα and may therefore be useful in the treatment of estrogen sensitive diseases or conditions (including diseases that have developed resistance to endocrine therapies), i.e. for use in the treatment of cancer of the breast and gynaecological cancers (including endometrial, ovarian and cervical) and cancers expressing ERα mutated proteins which may be de novo mutations or have arisen as a result of treatment with a prior endocrine therapy such as an aromatase inhibitor.

According to a further aspect of the specification there is provided a compound of the Formula (I), (IA), (IB), (IC) or (ID), or a pharmaceutically acceptable salt thereof, as defined hereinbefore, for use in the treatment of breast or gynaecological cancers.

According to a further aspect of the specification there is provided a compound of the Formula (I), (IA), (IB), (IC) or (ID), or a pharmaceutically acceptable salt thereof, as defined hereinbefore, for use in the treatment of cancer of the breast, endometrium, ovary or cervix.

According to a further aspect of the specification there is provided a compound of the Formula (I), (IA), (IB), (IC) or (ID), or a pharmaceutically acceptable salt thereof, as defined hereinbefore, for use in the treatment of cancer of the breast.

According to a further aspect of the specification there is provided a compound of the Formula (I), (IA), (IB), (IC) or (ID), or a pharmaceutically acceptable salt thereof, as defined hereinbefore, for use in the treatment of cancer of the breast, wherein the cancer has developed resistance to one or more other endocrine therapies.

According to a further aspect of the specification there is provided a method for treating breast or gynaecological cancers, which comprises administering an effective amount of a compound of the Formula (I), (IA), (IB), (IC) or (ID), or a pharmaceutically acceptable salt thereof, as defined hereinbefore.

According to a further aspect of the specification there is provided a method for treating cancer of the breast, endometrium, ovary or cervix, which comprises administering an effective amount of a compound of the Formula (I), (IA), (IB), (IC) or (ID), or a pharmaceutically acceptable salt thereof, as defined hereinbefore.

According to a further aspect of the specification there is provided a method for treating breast cancer, which comprises administering an effective amount of a compound of the Formula (I), (IA), (IB), (IC) or (ID), or a pharmaceutically acceptable salt thereof, as defined hereinbefore.

According to a further aspect of the specification there is provided a method for treating breast cancer, wherein the cancer has developed resistance to one or more other endocrine therapies, which comprises administering an effective amount of a compound of the Formula (I), (IA), (IB), (IC) or (ID), or a pharmaceutically acceptable salt thereof, as defined hereinbefore.

According to a further aspect of the specification there is provided the use of a compound of the Formula (I), (IA), (IB), (IC) or (ID), or a pharmaceutically acceptable salt thereof, as defined hereinbefore, in the manufacture of a medicament for use in the treatment of breast or gynaecological cancers.

According to a further aspect of the specification there is provided the use of a compound of the Formula (I), (IA), (IB), (IC) or (ID), or a pharmaceutically acceptable salt thereof, as defined hereinbefore, in the manufacture of a medicament for use in the treatment of cancer of the breast, endometrium, ovary or cervix.

According to a further aspect of the specification there is provided the use of a compound of the Formula (I), (IA), (IB), (IC) or (ID), or a pharmaceutically acceptable salt thereof, as defined hereinbefore, in the manufacture of a medicament for use in the treatment of breast cancer.

According to a further aspect of the specification there is provided the use of a compound of the Formula (I), (IA), (IB), (IC) or (ID), or a pharmaceutically acceptable salt thereof, as defined hereinbefore, in the manufacture of a medicament for use in the treatment of breast cancer, wherein the cancer has developed resistance to one or more other endocrine therapies.

In one feature of the specification, the cancer to be treated is breast cancer. In a further aspect of this feature, the breast cancer is Estrogen Receptor +ve (ER+ve). In one embodiment of this aspect, the compound of Formula (I), (IA), (IB), (IC) or (ID), is dosed in combination with another anticancer agent, such as an anti-hormonal agent as defined herein.

According to a further aspect of the specification there is provided a compound of the Formula (I), (IA), (IB), (IC) or (ID), or a pharmaceutically acceptable salt thereof, as defined hereinbefore, for use in the treatment of ER+ve breast cancer.

According to a further aspect of the specification there is provided a method for treating ER+ve breast cancer, which comprises administering an effective amount of a compound of the Formula (I), (IA), (IB), (IC) or (ID), or a pharmaceutically acceptable salt thereof, as defined hereinbefore.

According to a further aspect of the specification there is provided the use of a compound of the Formula (I), (IA), (IB), (IC) or (ID), or a pharmaceutically acceptable salt thereof, as defined herein before in the manufacture of a medicament for use in the treatment of ER+ve breast cancer.

As stated hereinbefore, the in-vivo effects of a compound of the Formula (I), (IA), (IB), (IC) or (ID), may be exerted in part by one or more metabolites that are formed within the human or animal body after administration of a compound of the Formula (I), (IA), (IB), (IC) or (ID).

The present specification therefore also contemplates a method for inhibiting ER-α in a patient, comprising administering to a patient an amount of a compound of Formula (I), (IA), (IB), (IC) or (ID), or a pharmaceutically acceptable salt thereof, effective in inhibiting ER-α in the patient.

The present specification therefore also contemplates a method for inhibiting ER-α in a patient, comprising administering to a patient an amount of a compound of Formula (I), (IA), (IB), (IC) or (ID), or a pharmaceutically acceptable salt thereof, effective in inhibiting ER-α in the patient.

The anti-cancer treatment defined herein may be applied as a sole therapy or may involve, in addition to the compounds of the specification, conventional surgery or radiotherapy or chemotherapy. Such chemotherapy may include one or more of the following categories of anti-tumour agents:—

(i) other antiproliferative/antineoplastic drugs and combinations thereof, as used in medical oncology, such as alkylating agents (for example cis-platin, oxaliplatin, carboplatin, cyclophosphamide, nitrogen mustard, melphalan, chlorambucil, busulphan, temozolamide and nitrosoureas); antimetabolites (for example gemcitabine and antifolates such as fluoropyrimidines like 5-fluorouracil and tegafur, raltitrexed, methotrexate, cytosine arabinoside, and hydroxyurea); antitumour antibiotics (for example anthracyclines like adriamycin, bleomycin, doxorubicin, daunomycin, epirubicin, idarubicin, mitomycin-C, dactinomycin and mithramycin); antimitotic agents (for example vinca alkaloids like vincristine, vinblastine, vindesine and vinorelbine and taxoids like taxol and taxotere and polokinase inhibitors); and topoisomerase inhibitors (for example epipodophyllotoxins like etoposide and teniposide, amsacrine, topotecan and camptothecin); (ii) anti-hormonal agents such as anti-oestrogens (for example tamoxifen, fulvestrant, toremifene, raloxifene, droloxifene and iodoxyfene), progestogens (for example megestrol acetate), aromatase inhibitors (for example as anastrozole, letrozole, vorazole and exemestane); (iii) inhibitors of growth factor function and their downstream signalling pathways: included are Ab modulators of any growth factor or growth factor receptor targets, reviewed by Stern et al. Critical Reviews in Oncology/Haematology, 2005, 54, pp 11-29); also included are small molecule inhibitors of such targets, for example kinase inhibitors—examples include the anti-erbB2 antibody trastuzumab [Herceptin™], the anti-EGFR antibody panitumumab, the anti-EGFR antibody cetuximab [Erbitux, C225] and tyrosine kinase inhibitors including inhibitors of the erbB receptor family, such as epidermal growth factor family receptor (EGFR/erbB1) tyrosine kinase inhibitors such as gefitinib or erlotinib, erbB2 tyrosine kinase inhibitors such as lapatinib, and mixed erb1/2 inhibitors such as afatanib; similar strategies are available for other classes of growth factors and their receptors, for example inhibitors of the hepatocyte growth factor family or their receptors including c-met and ron; inhibitors of the insulin and insulin growth factor family or their receptors (IGFR, IR) inhibitors of the platelet-derived growth factor family or their receptors (PDGFR), and inhibitors of signalling mediated by other receptor tyrosine kinases such as c-kit, AnLK, and CSF-1R; also included are modulators which target signalling proteins in the PI3-kinase signalling pathway, for example, inhibitors of PI3-kinase isoforms such as PI3K-α/β/γ and ser/thr kinases such as AKT, mTOR (such as AZD2014), PDK, SGK, PI4K or PIPSK; also included are inhibitors of serine/threonine kinases not listed above, for example raf inhibitors such as vemurafenib, MEK inhibitors such as selumetinib (AZD6244), Abl inhibitors such as imatinib or nilotinib, Btk inhibitors such as ibrutinib, Syk inhibitors such as fostamatinib, aurora kinase inhibitors (for example AZD1152), inhibitors of other ser/thr kinases such as JAKs, STATs and IRAK4, and cyclin dependent kinase inhibitors for example inhibitors of CDK1, CDK7, CDK9 and CDK4/6 such as palbociclib; iv) modulators of DNA damage signalling pathways, for example PARP inhibitors (e.g. Olaparib), ATR inhibitors or ATM inhibitors; v) modulators of apoptotic and cell death pathways such as Bcl family modulators (e.g. ABT-263/Navitoclax, ABT-199); (vi) anti-angiogenic agents such as those which inhibit the effects of vascular endothelial growth factor, [for example the anti-vascular endothelial cell growth factor antibody bevacizumab (Avastin™) and for example, a VEGF receptor tyrosine kinase inhibitor such as sorafenib, axitinib, pazopanib, sunitinib and vandetanib (and compounds that work by other mechanisms (for example linomide, inhibitors of integrin αvβ3 function and angiostatin)]; (vii) vascular damaging agents, such as Combretastatin A4; (viii) anti-invasion agents, for example c-Src kinase family inhibitors like (dasatinib, J. Med. Chem., 2004, 47, 6658-6661) and bosutinib (SKI-606), and metalloproteinase inhibitors like marimastat, inhibitors of urokinase plasminogen activator receptor function or antibodies to Heparanase]; (ix) immunotherapy approaches, including for example ex-vivo and in-vivo approaches to increase the immunogenicity of patient tumour cells, such as transfection with cytokines such as interleukin 2, interleukin 4 or granulocyte-macrophage colony stimulating factor, approaches to decrease T-cell anergy, approaches using transfected immune cells such as cytokine-transfected dendritic cells, approaches using cytokine-transfected tumour cell lines and approaches using anti-idiotypic antibodies. Specific examples include monoclonal antibodies targeting PD-1 (e.g. BMS-936558) or CTLA4 (e.g. ipilimumab and tremelimumab); (x) Antisense or RNAi based therapies, for example those which are directed to the targets listed. (xi) gene therapy approaches, including for example approaches to replace aberrant genes such as aberrant p53 or aberrant BRCA1 or BRCA2, GDEPT (gene-directed enzyme pro-drug therapy) approaches such as those using cytosine deaminase, thymidine kinase or a bacterial nitroreductase enzyme and approaches to increase patient tolerance to chemotherapy or radiotherapy such as multi-drug resistance gene therapy.

Accordingly, in one embodiment there is provided a compound of Formula (I), (IA), (IB), (IC) or (ID), or a pharmaceutically acceptable salt thereof, and an additional anti-tumour substance for the conjoint treatment of cancer.

According to this aspect of the specification there is provided a combination suitable for use in the treatment of cancer comprising a compound of the Formula (I) (IA), (IB), (IC) or (ID), or a pharmaceutically acceptable salt thereof and another anti-tumour agent, in particular any one of the anti tumour agents listed under (i)-(xi) above. In particular, the anti-tumour agent listed under (i)-(xi) above is the standard of care for the specific cancer to be treated; the person skilled in the art will understand the meaning of “standard of care”.

Therefore in a further aspect of the specification there is provided a compound of the Formula (I), (IA), (IB), (IC) or (ID), or a pharmaceutically acceptable salt thereof, in combination with another anti-tumour agent, in particular an anti-tumour agent selected from one listed under (i)-(xi) herein above.

In a further aspect of the specification there is provided a compound of the Formula (I), (IA), (IB), (IC) or (ID), or a pharmaceutically acceptable salt thereof, in combination with another anti-tumour agent, in particular an anti-tumour agent selected from one listed under (i) above.

In a further aspect of the specification there is provided a compound of the Formula (I), (IA), (IB), (IC) or (ID), or a pharmaceutically acceptable salt thereof, and any one of the anti-tumour agents listed under (i) above.

In a further aspect of the specification there is provided a combination suitable for use in the treatment of cancer comprising a compound of the Formula (I), (IA), (IB), (IC) or (ID), or a pharmaceutically acceptable salt thereof, and a taxoid, such as for example taxol or taxotere, conveniently taxotere.

In a further aspect of the specification there is provided a compound of the Formula (I), (IA), (IB), (IC) or (ID), or a pharmaceutically acceptable salt thereof, in combination with another anti-tumour agent, in particular an anti-tumour agent selected from one listed under (ii) herein above.

In a further aspect of the specification there is provided a combination suitable for use in the treatment of cancer comprising a compound of the Formula (I), (IA), (IB), (IC) or (ID), or a pharmaceutically acceptable salt thereof, and any one of the anti-hormonal agents listed under (ii) above, for example any one of the anti-oestrogens listed in (ii) above, or for example an aromatase inhibitor listed in (ii) above.

In a further aspect of the specification there is provided a combination suitable for use in the treatment of cancer comprising a compound of the Formula (I), (IA), (IB), (IC) or (ID), or a pharmaceutically acceptable salt thereof, and an mTOR inhibitor, such as AZD2014 (see for example WO2008/023161).

In a further aspect of the specification there is provided a combination suitable for use in the treatment of cancer comprising a compound of the Formula (I), (IA), (IB), (IC) or (ID), or a pharmaceutically acceptable salt thereof, and a PI3Kα-inhibitor, such as the compound 1-(4-(5-(5-amino-6-(5-tert-butyl-1,3,4-oxadiazol-2-yl)pyrazin-2-yl)-1-ethyl-1H-1,2,4-triazol-3-yl)piperidin-1-yl)-3-hydroxypropan-1-one, or a pharmaceutically-acceptable salt thereof.

In a further aspect of the specification there is provided a combination suitable for use in the treatment of cancer comprising a compound of the Formula (I), (IA), (IB), (IC) or (ID), or a pharmaceutically acceptable salt thereof, and palbociclib.

In one aspect the above combination of a compound of the Formula (I), (IA), (IB), (IC) or (ID), or a pharmaceutically acceptable salt thereof, with an anti-tumour agent listed in (ii) above, or an mTOR inhibitor (such as AZD2014), or a PI3K-α inhibitor (such as the compound 1-(4-(5-(5-amino-6-(5-tert-butyl-1,3,4-oxadiazol-2-yl)pyrazin-2-yl)-1-ethyl-1H-1,2,4-triazol-3-yl)piperidin-1-yl)-3-hydroxypropan-1-one) or palbociclib, is suitable for use in the treatment of breast or gynaecological cancers, such as cancer of the breast, endometrium, ovary or cervix, particularly breast cancer, such as ER+ve breast cancer.

Herein, where the term “combination” is used it is to be understood that this refers to simultaneous, separate or sequential administration. In one aspect of the specification “combination” refers to simultaneous administration. In another aspect of the specification “combination” refers to separate administration. In a further aspect of the specification “combination” refers to sequential administration. Where the administration is sequential or separate, the delay in administering the second component should not be such as to lose the beneficial effect of the combination. Where a combination of two or more components is administered separately or sequential, it will be understood that the dosage regime for each component may be different to and independent of the other components. Conveniently, the compounds of the present specification are dosed once daily.

According to a further aspect of the specification there is provided a pharmaceutical composition which comprises a compound of Formula (I), (IA), (IB), (IC) or (ID), or a pharmaceutically acceptable salt thereof in combination with an anti-tumour agent selected from one listed under (i)-(xi) herein above, in association with a pharmaceutically acceptable excipient.

According to a further aspect of the specification there is provided a pharmaceutical composition which comprises a compound of Formula (I), (IA), (IB), (IC) or (ID), or a pharmaceutically acceptable salt thereof in combination with any one of antihormonal agents listed under (ii) above, for example any one of the anti-oestrogens listed in (ii) above, or for example an aromatase inhibitor listed in (ii) above in association with a pharmaceutically acceptable excipient.

In a further aspect of the specification there is provided a pharmaceutical composition comprising a compound of the Formula (I), (IA), (IB), (IC) or (ID), or a pharmaceutically acceptable salt thereof, and an mTOR inhibitor, such as AZD2014 (see for example WO2008/023161); in association with a pharmaceutically acceptable excipient.

In a further aspect of the specification there is provided a pharmaceutical composition comprising a compound of the Formula (I), (IA), (IB), (IC) or (ID), or a pharmaceutically acceptable salt thereof, and a PI3Kα-inhibitor, such as the compound 1-(4-(5-(5-amino-6-(5-tert-butyl-1,3,4-oxadiazol-2-yl)pyrazin-2-yl)-1-ethyl-1H-1,2,4-triazol-3-yl)piperidin-1-yl)-3-hydroxypropan-1-one, in association with a pharmaceutically acceptable excipient.

In a further aspect of the specification there is provided a pharmaceutical composition comprising a compound of the Formula (I), (IA), (IB), (IC) or (ID), or a pharmaceutically acceptable salt thereof, and palbociclib in association with a pharmaceutically acceptable excipient.

According to a further aspect of the specification there is provided a pharmaceutical composition which comprises a compound of the Formula (I), (IA), (IB), (IC) or (ID), or a pharmaceutically acceptable salt thereof, in combination with an anti-tumour agent selected from one listed under (i)-(xi) herein above, in association with a pharmaceutically acceptable excipient for use in treating cancer.

According to a further aspect of the specification there is provided a pharmaceutical composition which comprises a compound of the Formula (I), (IA), (IB), (IC) or (ID), or a pharmaceutically acceptable salt thereof, in combination with any one of anti-hormonal agents listed under (ii) above, for example any one of the anti-oestrogens listed in (ii) above, or for example an aromatase inhibitor listed in (ii) above in association with a pharmaceutically acceptable excipient for use in treating cancer.

In a further aspect of the specification there is provided a pharmaceutical composition comprising a compound of the Formula (I), (IA), (IB), (IC) or (ID), or a pharmaceutically acceptable salt thereof, and an mTOR inhibitor, such as AZD2014 (see for example WO2008/023161); in association with a pharmaceutically acceptable excipient for use in treating cancer.

In a further aspect of the specification there is provided a pharmaceutical composition comprising a compound of the Formula (I), (IA), (IB), (IC) or (ID), or a pharmaceutically acceptable salt thereof, and a PI3Kα-inhibitor, such as the compound 1-(4-(5-(5-amino-6-(5-tert-butyl-1,3,4-oxadiazol-2-yl)pyrazin-2-yl)-1-ethyl-1H-1,2,4-triazol-3-yl)piperidin-1-yl)-3-hydroxypropan-1-one, in association with a pharmaceutically acceptable excipient for use in treating cancer.

In a further aspect of the specification there is provided a pharmaceutical composition comprising a compound of the Formula (I), (IA), (IB), (IC) or (ID), or a pharmaceutically acceptable salt thereof, and palbociclib in association with a pharmaceutically acceptable excipient for use in treating cancer.

In one aspect the above pharmaceutical compositions of a compound of the Formula (I), (IA), (IB), (IC) or (ID), or a pharmaceutically acceptable salt thereof, with an anti-tumour agent listed in (ii) above, or an mTOR inhibitor (such as AZD2014), or a PI3K-α inhibitor (such as the compound 1-(4-(5-(5-amino-6-(5-tert-butyl-1,3,4-oxadiazol-2-yl)pyrazin-2-yl)-1-ethyl-1H-1,2,4-triazol-3-yl)piperidin-1-yl)-3-hydroxypropan-1-one) or palbociclib, is suitable for use in the treatment of breast or gynaecological cancers, such as cancer of the breast, endometrium, ovary or cervix, particularly breast cancer, such as ER+ve breast cancer.

According to another feature of the specification there is provided the use of a compound of the Formula (I), (IA), (IB), (IC) or (ID), or a pharmaceutically acceptable salt thereof in combination with an anti-tumour agent selected from one listed under (i)-(xi) herein above, in the manufacture of a medicament for use in the treatment of cancer in a warm-blooded animal, such as man.

According to a further aspect of the specification there is provided the use of a compound of Formula (I), (IA), (IB), (IC) or (ID), or a pharmaceutically acceptable salt thereof in combination with any one of antihormonal agents listed under (ii) above, for example any one of the anti-oestrogens listed in (ii) above, or for example an aromatase inhibitor listed in (ii) above in the manufacture of a medicament for use in the treatment of cancer in a warm-blooded animal, such as man.

In a further aspect of the specification there is provided the use of a compound of the Formula (I), (IA), (IB), (IC) or (ID), or a pharmaceutically acceptable salt thereof, in combination with an mTOR inhibitor, such as AZD2014 (see for example WO2008/023161); in the manufacture of a medicament for use in the treatment of cancer in a warm-blooded animal, such as man.

In a further aspect of the specification there is provided the use of a compound of the Formula (I), (IA), (IB), (IC) or (ID), or a pharmaceutically acceptable salt thereof, in combination with a PI3Kα-inhibitor, such as the compound 1-(4-(5-(5-amino-6-(5-tert-butyl-1,3,4-oxadiazol-2-yl)pyrazin-2-yl)-1-ethyl-1H-1,2,4-triazol-3-yl)piperidin-1-yl)-3-hydroxypropan-1-one, in the manufacture of a medicament for use in the treatment of cancer in a warm-blooded animal, such as man.

In a further aspect of the specification there is provided the use a compound of the Formula (I), (IA), (IB), (IC) or (ID), or a pharmaceutically acceptable salt thereof, in combination with palbociclib in the manufacture of a medicament for use in the treatment of cancer in a warm-blooded animal, such as man.

In one aspect the above uses of a compound of the Formula (I), (IA), (IB), (IC) or (ID), or a pharmaceutically acceptable salt thereof, in combination with an anti-tumour agent listed in (ii) above, or an mTOR inhibitor (such as AZD2014), or a PI3K-α inhibitor (such as the compound 1-(4-(5-(5-amino-6-(5-tert-butyl-1,3,4-oxadiazol-2-yl)pyrazin-2-yl)-1-ethyl-1H-1,2,4-triazol-3-yl)piperidin-1-yl)-3-hydroxypropan-1-one) or palbociclib, is suitable for use in the manufacture of a medicament for the treatment of breast or gynaecological cancers, such as cancer of the breast, endometrium, ovary or cervix, particularly breast cancer, such as ER+ve breast cancer.

Therefore in an additional feature of the specification, there is provided a method of treating cancer in a warm-blooded animal, such as man, in need of such treatment which comprises administering to said animal an effective amount of a compound of the Formula (I), (IA), (IB), (IC) or (ID), or a pharmaceutically acceptable salt thereof, in combination with an anti-tumour agent selected from one listed under (i)-(xi) herein above.

According to a further aspect of the specification there is provided a method of treating cancer in a warm-blooded animal, such as man, in need of such treatment which comprises administering to said animal an effective amount of a compound of Formula (I), (IA), (IB), (IC) or (ID), or a pharmaceutically acceptable salt thereof in combination with any one of anti-hormonal agents listed under (ii) above, for example any one of the anti-oestrogens listed in (ii) above, or for example an aromatase inhibitor listed in (ii) above.

In a further aspect of the specification there is provided a method of treating cancer in a warm-blooded animal, such as man, in need of such treatment which comprises administering to said animal an effective amount of a compound of the Formula (I), (IA), (IB), (IC) or (ID), or a pharmaceutically acceptable salt thereof, in combination with an mTOR inhibitor, such as AZD2014 (see for example WO2008/023161).

In a further aspect of the specification there provided a method of treating cancer in a warm-blooded animal, such as man, in need of such treatment which comprises administering to said animal an effective amount of a compound of the Formula (I), (IA), (IB), (IC) or (ID), or a pharmaceutically acceptable salt thereof, in combination with a PI3Kα-inhibitor, such as the compound 1-(4-(5-(5-amino-6-(5-tert-butyl-1,3,4-oxadiazol-2-yl)pyrazin-2-yl)-1-ethyl-1H-1,2,4-triazol-3-yl)piperidin-1-yl)-3-hydroxypropan-1-one.

In a further aspect of the specification there is provided a method of treating cancer in a warm-blooded animal, such as man, in need of such treatment which comprises administering to said animal an effective amount of a compound of the Formula (I), (IA), (IB), (IC) or (ID), or a pharmaceutically acceptable salt thereof, in combination with palbociclib.

In one aspect the above combinations, pharmaceutical compositions, uses and methods of treating cancer, are methods for the treatment of breast or gynaecological cancers, such as cancer of the breast, endometrium, ovary or cervix, particularly breast cancer, such as ER+ve breast cancer.

According to a further aspect of the present specification there is provided a kit comprising a compound of Formula (I), (IA), (IB), (IC) or (ID), or a pharmaceutically acceptable salt thereof, in combination with an anti-tumour agent selected from one listed under (i)-(xi) herein above.

According to a further aspect of the present specification there is provided a kit comprising a compound of Formula (I), (IA), (IB), (IC) or (ID), or a pharmaceutically acceptable salt thereof, in combination with an anti-tumour agent selected from one listed under (i) or (ii) herein above.

According to a further aspect of the present specification there is provided a kit comprising:

a) a compound of Formula (I), (IA), (IB), (IC) or (ID), or a pharmaceutically acceptable salt thereof, in a first unit dosage form;

b) an anti-tumour agent selected from one listed under (i)-(xi) herein above in a second unit dosage form; and

c) container means for containing said first and second dosage forms.

According to a further aspect of the present specification there is provided a kit comprising:

a) a compound of Formula (I), (IA), (IB), (IC) or (ID), or a pharmaceutically acceptable salt thereof, in a first unit dosage form;

b) an anti-tumour agent selected from one listed under (i) (ii) herein above in a second unit dosage form; and

c) container means for containing said first and second dosage forms.

According to a further aspect of the present specification there is provided a kit comprising:

a) a compound of the Formula (I), (IA), (IB), (IC) or (ID), or a pharmaceutically acceptable salt thereof, in a first unit dosage form;

b) an anti-tumour agent selected from an anti-tumour agent listed in (ii) above, an mTOR inhibitor (such as AZD2014), a PI3Kα-inhibitor, such as the compound 1-(4-(5-(5-amino-6-(5-tert-butyl-1,3,4-oxadiazol-2-yl)pyrazin-2-yl)-1-ethyl-1H-1,2,4-triazol-3-yl)piperidin-1-yl)-3-hydroxypropan-1-one, and palbociclib, in a second unit dosage form; and c) container means for containing said first and second dosage forms.

Combination therapy as described above may be added on top of standard of care therapy typically carried out according to its usual prescribing schedule.

Although the compounds of the Formula (I), (IA), (IB), (IC) or (ID), are primarily of value as therapeutic agents for use in warm-blooded animals (including man), they are also useful whenever it is required to inhibit ER-α. Thus, they are useful as pharmacological standards for use in the development of new biological tests and in the search for new pharmacological agents.

Personalised Healthcare

Another aspect of the present specification is based on identifying a link between the status of the gene encoding ERα and potential susceptibility to treatment with a compound of Formula (I), (IA), (IB), (IC) or (ID). In particular, ERα gene status may indicate that a patient is less likely to respond to existing hormone therapy (such as aromatase inhibitors), in part at least because some ERα mutations are though to arise as resistance mechanisms to existing treatments. A SERD, particularly a SERD which can be administered orally in potentially larger doses without excessive inconvenience, may then advantageously be used to treat patients with ERα mutations who may be resistant to other therapies. This therefore provides opportunities, methods and tools for selecting patients for treatment with a compound of Formula (I), (IA), (IB), (IC) or (ID), particularly cancer patients. The present specification relates to patient selection tools and methods (including personalised medicine). The selection is based on whether the tumour cells to be treated possess wild-type or mutant ERα gene. The ERα gene status could therefore be used as a biomarker to indicate that selecting treatment with a SERD may be advantageous. For the avoidance of doubt, compounds of the Formula (I), (IA), (IB), (IC) or (ID), as described herein are thought to be similarly active against wild-type and mutant ERα genes, at least those mutations in ERα gene identified at the date of filing this application.

There is a clear need for biomarkers that will enrich for or select patients whose tumours will respond to treatment with a SERD, such as a compound of Formula (I), (IA), (IB), (IC) or (ID). Patient selection biomarkers that identify the patients most likely to respond to one agent over another are ideal in the treatment of cancer, since they reduce the unnecessary treatment of patients with non-responding tumours to the potential side effects of such agents.

A biomarker can be described as “a characteristic that is objectively measured and evaluated as an indicator of normal biologic processes, pathogenic processes, or pharmacologic responses to a therapeutic intervention”. A biomarker is any identifiable and measurable indicator associated with a particular condition or disease where there is a correlation between the presence or level of the biomarker and some aspect of the condition or disease (including the presence of, the level or changing level of, the type of, the stage of, the susceptibility to the condition or disease, or the responsiveness to a drug used for treating the condition or disease). The correlation may be qualitative, quantitative, or both qualitative and quantitative. Typically a biomarker is a compound, compound fragment or group of compounds. Such compounds may be any compounds found in or produced by an organism, including proteins (and peptides), nucleic acids and other compounds.

Biomarkers may have a predictive power, and as such may be used to predict or detect the presence, level, type or stage of particular conditions or diseases (including the presence or level of particular microorganisms or toxins), the susceptibility (including genetic susceptibility) to particular conditions or diseases, or the response to particular treatments (including drug treatments). It is thought that biomarkers will play an increasingly important role in the future of drug discovery and development, by improving the efficiency of research and development programs. Biomarkers can be used as diagnostic agents, monitors of disease progression, monitors of treatment and predictors of clinical outcome. For example, various biomarker research projects are attempting to identify markers of specific cancers and of specific cardiovascular and immunological diseases. It is believed that the development of new validated biomarkers will lead both to significant reductions in healthcare and drug development costs and to significant improvements in treatment for a wide variety of diseases and conditions.

In order to optimally design clinical trials and to gain the most information from these trials, a biomarker may be required. The marker may be measurable in surrogate and tumour tissues. Ideally these markers will also correlate with efficacy and thus could ultimately be used for patient selection.

Thus, the technical problem underlying this aspect of the present specification is the identification of means for stratification of patients for treatment with a compound of Formula (I). The technical problem is solved by provision of the embodiments characterized in the claims and/or description herein.

Tumours which contain wild type ERα are believed to be susceptible to treatment with a compound of Formula (I), (IA), (IB), (IC) or (ID), for example as a first-line treatment. Tumours may also respond to treatment with a compound of Formula (I), (IA), (IB), (IC) or (ID), as a second-line, third-line or subsequent therapy and this may be useful, in particular, where the tumours contain mutant ERα and may thus be resistant to existing therapies such as AIs. A higher dosage of a compound of Formula (I), (IA), (IB), (IC) or (ID), may be required in the resistant setting than in wild type tumours).

The specification provides a method of determining sensitivity of cells to a compound of Formula (I), (IA), (IB), (IC) or (ID). The method comprises determining the status of ERα gene in said cells. A cell is defined as sensitive to a compound of Formula (I), (IA), (IB), (IC) or (ID), if it inhibits the increase in cell number in a cell growth assay (either through inhibition of cell proliferation and/or through increased cell death). Methods of the specification are useful for predicting which cells are more likely to respond to a compound of Formula (I), (IA), (IB), (IC) or (ID), by growth inhibition.

A sample “representative of the tumour” can be the actual tumour sample isolated, or may be a sample that has been further processed, e.g. a sample of PCR amplified nucleic acid from the tumour sample.

Definitions

In this Personalised Healthcare section:

“Allele” refers to a particular form of a genetic locus, distinguished from other forms by its particular nucleotide or amino acid sequence.

“Amplification reactions” are nucleic acid reactions which result in specific amplification of target nucleic acids over non-target nucleic acids. The polymerase chain reaction (PCR) is a well known amplification reaction.

“Cancer” is used herein to refer to neoplastic growth arising from cellular transformation to a neoplastic phenotype. Such cellular transformation often involves genetic mutation.

“Gene” is a segment of DNA that contains all the information for the regulated biosynthesis of an RNA product, including a promoter, exons, introns, and other sequence elements which may be located within 5′ or 3′ flanking regions (not within the transcribed portions of the gene) that control expression.

“Gene status” refers to whether the gene is wild type or not (i.e. mutant).

“Label” refers to a composition capable of producing a detectable signal indicative of the presence of the target polynucleotide in an assay sample. Suitable labels include radioisotopes, nucleotide chromophores, enzymes, substrates, fluorescent molecules, chemiluminescent moieties, magnetic particles, bioluminescent moieties, and the like. As such, a label is any composition detectable by spectroscopic, photochemical, biochemical, immunochemical, electrical, optical or chemical means.

“Non-synonymous variation” refers to a variation (variance) in or overlapping the coding sequence of a gene that result in the production of a distinct (altered) polypeptide sequence. These variations may or may not affect protein function and include missense variants (resulting in substitution of one amino acid for another), nonsense variants (resulting in a truncated polypeptide due to generation of a premature stop codon) and insertion/deletion variants.

“Synonymous variation” refers to a variation (variance) in the coding sequence of a gene that does not affect sequence of the encoded polypeptide. These variations may affect protein function indirectly (for example by altering expression of the gene), but, in the absence of evidence to the contrary, are generally assumed to be innocuous.

“Nucleic acid” refers to single stranded or double stranded DNA and RNA molecules including natural nucleic acids found in nature and/or modified, artificial nucleic acids having modified backbones or bases, as are known in the art.

“Primer” refers to a single stranded DNA oligonucleotide sequence capable of acting as a point of initiation for synthesis of a primer extension product which is complementary to the nucleic acid strand to be copied. The length and sequence of the primer must be such that they are able to prime the synthesis of extension products. A typical primer contains at least about 7 nucleotides in length of a sequence substantially complementary to the target sequence, but somewhat longer primers are preferred. Usually primers contain about 15-26 nucleotides, but longer or shorter primers may also be employed.

“Polymorphic site” is a position within a locus at which at least two alternative sequences are found in a population.

“Polymorphism” refers to the sequence variation observed in an individual at a polymorphic site. Polymorphisms include nucleotide substitutions, insertions, deletions and microsatellites and may, but need not, result in detectable differences in gene expression or protein function. In the absence of evidence of an effect on expression or protein function, common polymorphisms, including non-synonymous variants, are generally considered to be included in the definition of wild-type gene sequence. A catalog of human polymorphisms and associated annotation, including validation, observed frequencies, and disease association, is maintained by NCBI (dbSNP: http://www.ncbi.nlm.nih.gov/projects/SNP/). Please note that the term “polymorphism” when used in the context of gene sequences should not be confused with the term “polymorphism” when used in the context of solid state form of a compound that is the crystalline or amorphous nature of a compound. The skilled person will understand the intended meaning by its context.

“Probe” refers to single stranded sequence-specific oligonucleotides which have a sequence that is exactly complementary to the target sequence of the allele to be detected.

“Response” is defined by measurements taken according to Response Evaluation Criteria in Solid Tumours (RECIST) involving the classification of patients into two main groups: those that show a partial response or stable disease and those that show signs of progressive disease.

“Stringent hybridisation conditions” refers to an overnight incubation at 42° C. in a solution comprising 50% formamide, 5×SSC (750 mM NaCl, 75 mM trisodium citrate), 50 mM sodium phosphate (pH 7.6), 5×Denhardt's solution, 10% dextran sulphate, and 20 pg/ml denatured, sheared salmon sperm DNA, followed by washing the filters in 0.1×SSC at about 65° C.

“Survival” encompasses a patients' overall survival and progression-free survival.

“Overall survival” (OS) is defined as the time from the initiation of drug administration to death from any cause. “Progression-free survival” (PFS) is defined as the time from the initiation of drug administration to first appearance of progressive disease or death from any cause.

According to one aspect of the specification there is provided a method for selecting a patient for treatment with a compound of Formula (I), (IA), (IB), (IC) or (ID), the method comprising providing a tumour cell containing sample from a patient; determining whether the ERα gene in the patient's tumour cell containing sample is wild type or mutant; and selecting a patient for treatment with a compound of Formula (I), (IA), (IB), (IC) or (ID), based thereon.

The method may include or exclude the actual patient sample isolation step. Thus, according to one aspect of the specification there is provided a method for selecting a patient for treatment with a compound of Formula (I), (IA), (IB), (IC) or (ID), the method comprising determining whether the ERα gene in a tumour cell containing sample previously isolated from the patient is wild type or mutant; and selecting a patient for treatment with a compound of Formula (I), (IA), (IB), (IC) or (ID), based thereon.

In one embodiment, the patient is selected for treatment with a compound of Formula (I), (IA), (IB), (IC) or (ID), if the tumour cell DNA has a mutant ERα gene. In other embodiments, a patient whose tumour cell DNA possesses a wild type ERα gene is selected for treatment with a compound of Formula (I), (IA), (IB), (IC) or (ID).

For the purpose of this specification, a gene status of wild-type is meant to indicate normal or appropriate expression of the gene and normal function of the encoded protein. In contrast, mutant status is meant to indicate expression of a protein with altered function, consistent with the known roles of mutant ERα genes in cancer (as described herein). Any number of genetic or epigenetic alterations, including but not limited to mutation, amplification, deletion, genomic rearrangement, or changes in methylation profile, may result in a mutant status. However, if such alterations nevertheless result in appropriate expression of the normal protein, or a functionally equivalent variant, then the gene status is regarded as wild-type. Examples of variants that typically would not result in a functional mutant gene status include synonymous coding variants and common polymorphisms (synonymous or non-synonymous). As discussed below, gene status can be assessed by a functional assay, or it may be inferred from the nature of detected deviations from a reference sequence.

In certain embodiments the wild-type or mutant status of the ERα gene is determined by the presence or absence of non-synonymous nucleic acid variations in the genes. Observed non-synonymous variations corresponding to known common polymorphisms with no annotated functional effects do not contribute to a gene status of mutant.

Other variations in the ERα gene that signify mutant status include splice site variations that decrease recognition of an intron/exon junction during processing of pre-mRNA to mRNA. This can result in exon skipping or the inclusion of normally intronic sequence in spliced mRNA (intron retention or utilization of cryptic splice junctions). This can, in turn, result in the production of aberrant protein with insertions and/or deletions relative to the normal protein. Thus, in other embodiments, the gene has a mutant status if there is a variant that alters splice site recognition sequence at an intron/exon junction.

For ESR1, reference sequences are available for the gene (GenBank accession number: NG_008493), mRNA (GenBank accession number: NM_000125), and protein (GenBank accession number: NP_000116 or Swiss-Prot accession: P03372). A person of skill in the art will be able to determine the ESR1 gene status, i.e. whether a particular ESR1 gene is wild type or mutant, based on comparison of DNA or protein sequence with wild type.

It will be apparent that the gene and mRNA sequences disclosed for ERα gene are representative sequences. In normal individuals there are two copies of each gene, a maternal and paternal copy, which will likely have some sequence differences, moreover within a population there will exist numerous allelic variants of the gene sequence. Other sequences regarded as wild type include those that possess one or more synonymous changes to the nucleic acid sequence (which changes do not alter the encoded protein sequence), non-synonymous common polymorphisms (e.g. germ-line polymorphisms) which alter the protein sequence but do not affect protein function, and intronic non-splice-site sequence changes.

There are numerous techniques available to the person skilled in the art to determine the gene status of ERα. The gene status can be determined by determination of the nucleic acid sequence. This could be via direct sequencing of the full-length gene or analysis of specific sites within the gene, e.g. commonly mutated sites.

Samples

The patient's sample to be tested for the gene status can be any tumour tissue or tumour-cell containing sample obtained or obtainable from the individual. The test sample is conveniently a sample of blood, mouth swab, biopsy, or other body fluid or tissue obtained from an individual. Particular examples include: circulating tumour cells, circulating DNA in the plasma or serum, cells isolated from the ascites fluid of ovarian cancer patients, lung sputum for patients with tumours within the lung, a fine needle aspirate from a breast cancer patient, urine, peripheral blood, a cell scraping, a hair follicle, a skin punch or a buccal sample.

It will be appreciated that the test sample may equally be a nucleic acid sequence corresponding to the sequence in the test sample, that is to say that all or a part of the region in the sample nucleic acid may firstly be amplified using any convenient technique e.g. polymerase chain reaction (PCR), before analysis. The nucleic acid may be genomic DNA or fractionated or whole cell RNA. In particular embodiments the RNA is whole cell RNA and is used directly as the template for labelling a first strand cDNA using random primers or poly A primers. The nucleic acid or protein in the test sample may be extracted from the sample according to standard methodologies (see Green & Sambrook, Eds., Molecular Cloning: A Laboratory Manual, (2012, 4th edition, Vol. 1-3, ISBN 9781936113422), Cold Spring Harbor Laboratory Press, Cold Spring Harbor, N.Y.)

The diagnostic methods of the specification can be undertaken using a sample previously taken from the individual or patient. Such samples may be preserved by freezing or fixed and embedded in formalin-paraffin or other media. Alternatively, a fresh tumour cell containing sample may be obtained and used.

The methods of the specification can be applied using cells from any tumour. Suitable tumours for treatment with a compound of Formula (I), (IA), (IB), (IC) or (ID), have been described hereinbefore.

Methods for Detection of Nucleic Acids

The detection of mutant ERα nucleic acids can be employed, in the context of the present specification, to select drug treatment. Since mutations in these genes occur at the DNA level, the methods of the specification can be based on detection of mutations or variances in genomic DNA, as well as transcripts and proteins themselves. It can be desirable to confirm mutations in genomic DNA by analysis of transcripts and/or polypeptides, in order to ensure that the detected mutation is indeed expressed in the subject.

It will be apparent to the person skilled in the art that there are a large number of analytical procedures which may be used to detect the presence or absence of variant nucleotides at one or more positions in a gene. In general, the detection of allelic variation requires a mutation discrimination technique, optionally an amplification reaction (such as one based on polymerase chain reaction) and optionally a signal generation system. There are a multitude of mutation detection techniques available in the art and these may be used in combination with a signal generation system, of which there are numerous available in the art. Many methods for the detection of allelic variation are reviewed by Nollau et al., Clin. Chem., 1997, 43, 1114-1120; Anderson S M. Expert Rev Mol Diagn., 2011, 11, 635-642; Meyerson M. et al., Nat Rev Genet., 2010, 11, 685-696; and in standard textbooks, for example “Laboratory Protocols for Mutation Detection”, Ed. by U. Landegren, Oxford University Press, 1996 and “PCR”, 2^(nd) Edition by Newton & Graham, BIOS Scientific Publishers Limited, 1997.

As noted above, determining the presence or absence of a particular variance or plurality of variances in the ERα gene in a patient with cancer can be performed in a variety of ways. Such tests are commonly performed using DNA or RNA collected from biological samples, e.g., tissue biopsies, urine, stool, sputum, blood, cells, tissue scrapings, breast aspirates or other cellular materials, and can be performed by a variety of methods including, but not limited to, PCR, hybridization with allele-specific probes, enzymatic mutation detection, chemical cleavage of mismatches, mass spectrometry or DNA sequencing, including minisequencing.

Suitable mutation detection techniques include amplification refractory mutation system (ARMS™), amplification refractory mutation system linear extension (ALEX™) competitive oligonucleotide priming system (COPS), Taqman, Molecular Beacons, restriction fragment length polymorphism (RFLP), and restriction site based PCR and fluorescence resonance energy transfer (FRET) techniques.

In particular embodiments the method employed for determining the nucleotide(s) within a biomarker gene is selected from: allele-specific amplification (allele specific PCR)—such as amplification refractory mutation system (ARMS), sequencing, allelic discrimination assay, hybridisation, restriction fragment length polymorphism (RFLP) or oligonucleotide ligation assay (OLA).

In particular embodiments, hybridization with allele specific probes can be conducted by: (1) allele specific oligonucleotides bound to a solid phase (e.g. glass, silicon, nylon membranes) with the labelled sample in solution, for example as in many DNA chip applications; or, (2) bound sample (often cloned DNA or PCR amplified DNA) and labelled oligonucleotides in solution (either allele specific or short so as to allow sequencing by hybridization). Diagnostic tests may involve a panel of variances, often on a solid support, which enables the simultaneous determination of more than one variance. Such hybridization probes are well known in the art (see, e.g., Green & Sambrook, Eds., Molecular Cloning: A Laboratory Manual, (2012, 4th edition, Vol. 1-3, ISBN 9781936113422), Cold Spring Harbor Laboratory Press, Cold Spring Harbor, N.Y.) and may span two or more variance sites.

Thus, in one embodiment, the detection of the presence or absence of at least one mutation provides for contacting ERα nucleic acid containing a putative mutation site with at least one nucleic acid probe. The probe preferentially hybridizes with a nucleic acid sequence including a variance site and containing complementary nucleotide bases at the variance site under selective hybridization conditions. Hybridization can be detected with a detectable label using labels known to one skilled in the art. Such labels include, but are not limited to radioactive, fluorescent, dye, and enzymatic labels.

In another embodiment, the detection of the presence or absence of at least one mutation provides for contacting ERα nucleic acid containing a putative mutation site with at least one nucleic acid primer. The primer preferentially hybridizes with a nucleic acid sequence including a variance site and containing complementary nucleotide bases at the variance site under selective hybridization conditions.

Oligonucleotides used as primers for specific amplification may carry the complementary nucleotide base to the mutation of interest in the centre of the molecule (so that amplification depends on differential hybridization; see, e.g., Gibbs, et al., 1989. Nucl. Acids Res., 17, 2437-248) or at the extreme 3′-terminus of one primer where, under appropriate conditions, mismatch can prevent, or reduce polymerase extension (see, e.g., Prossner, 1993, Tibtech, 11 238).

In yet another embodiment, the detection of the presence or absence of at least one mutation comprises sequencing at least one nucleic acid sequence and comparing the obtained sequence with the known wild type nucleic acid sequence.

Alternatively, the presence or absence of at least one mutation comprises mass spectrometric determination of at least one nucleic acid sequence.

In one embodiment, the detection of the presence or absence of at least one nucleic acid variance comprises performing a polymerase chain reaction (PCR). The target nucleic acid sequence containing the hypothetical variance is amplified and the nucleotide sequence of the amplified nucleic acid is determined. Determining the nucleotide sequence of the amplified nucleic acid comprises sequencing at least one nucleic acid segment. Alternatively, amplification products can be analysed using any method capable of separating the amplification products according to their size, including automated and manual gel electrophoresis, and the like.

Mutations in genomic nucleic acid are advantageously detected by techniques based on mobility shift in amplified nucleic acid fragments. For instance, Chen et al., Anal Biochem 1996, 239, 61-9, describe the detection of single-base mutations by a competitive mobility shift assay. Moreover, assays based on the technique of Marcelino et al., BioTechniques 1999, 26, 1134-1148 are available commercially.

In a particular example, capillary heteroduplex analysis may be used to detect the presence of mutations based on mobility shift of duplex nucleic acids in capillary systems as a result of the presence of mismatches.

Generation of nucleic acids for analysis from samples generally requires nucleic acid amplification. Many amplification methods rely on an enzymatic chain reaction (such as a polymerase chain reaction, a ligase chain reaction, or a self-sustained sequence replication) or from the replication of all or part of the vector into which it has been cloned. Preferably, the amplification according to the specification is an exponential amplification, as exhibited by for example the polymerase chain reaction.

Many target and signal amplification methods have been described in the literature, for example, general reviews of these methods in Landegren, U., et al., Science, 1988 242, 229-237 and Lewis, R., Genetic Engineering News 1990, 10, 54-55. These amplification methods can be used in the methods of our specification, and include polymerase chain reaction (PCR), PCR in situ, ligase amplification reaction (LAR), ligase hybridisation, Qβ bacteriophage replicase, transcription-based amplification system (TAS), genomic amplification with transcript sequencing (GAWTS), nucleic acid sequence-based amplification (NASBA) and in situ hybridisation. Primers suitable for use in various amplification techniques can be prepared according to methods known in the art.

Polymerase Chain Reaction (PCR) PCR is a nucleic acid amplification method described inter alia in U.S. Pat. Nos. 4,683,195 and 4,683,202. PCR consists of repeated cycles of DNA polymerase generated primer extension reactions. The target DNA is heat denatured and two oligonucleotides, which bracket the target sequence on opposite strands of the DNA to be amplified, are hybridised. These oligonucleotides become primers for use with DNA polymerase. The DNA is copied by primer extension to make a second copy of both strands. By repeating the cycle of heat denaturation, primer hybridisation and extension, the target DNA can be amplified a million fold or more in about two to four hours. PCR is a molecular biology tool, which must be used in conjunction with a detection technique to determine the results of amplification. An advantage of PCR is that it increases sensitivity by amplifying the amount of target DNA by 1 million to 1 billion fold in approximately 4 hours. PCR can be used to amplify any known nucleic acid in a diagnostic context (Mok et al., Gynaecologic Oncology, 1994, 52: 247-252,).

An allele specific amplification technique such as Amplification Refractory Mutation System (ARMS™) (Newton et al., Nucleic Acids Res., 1989, 17, 2503-2516) can also be used to detect single base mutations. Under the appropriate PCR amplification conditions a single base mismatch located at the 3′-end of the primer is sufficient for preferential amplification of the perfectly matched allele (Newton et al., 1989, supra), allowing the discrimination of closely related species. The basis of an amplification system using the primers described above is that oligonucleotides with a mismatched 3′-residue will not function as primers in the PCR under appropriate conditions. This amplification system allows genotyping solely by inspection of reaction mixtures after agarose gel electrophoresis.

Analysis of amplification products can be performed using any method capable of separating the amplification products according to their size, including automated and manual gel electrophoresis, mass spectrometry, and the like.

The methods of nucleic acid isolation, amplification and analysis are routine for one skilled in the art and examples of protocols can be found, for example, Green & Sambrook, Eds., Molecular Cloning: A Laboratory Manual, (2012, 4th edition, Vol. 1-3, ISBN 9781936113422), Cold Spring Harbor Laboratory Press, Cold Spring Harbor, N.Y.) Particularly useful protocol source for methods used in PCR amplification is PCR (Basics: From Background to Bench) by M. J. McPherson, S. G. Mailer, R. Beynon, C. Howe, Springer Verlag; 1st edition (Oct. 15, 2000), ISBN: 0387916008.

The present specification also provides predictive and diagnostic kits comprising degenerate primers to amplify a target nucleic acid in the ERα gene and instructions comprising; amplification protocol and analysis of the results. The kit may alternatively also comprise buffers, enzymes, and containers for performing the amplification and analysis of the amplification products. The kit may also be a component of a screening, or diagnostic kit comprising other tools such as DNA microarrays, or other supports. Preferably, the kit also provides one or more control templates, such as nucleic acids isolated from normal tissue sample, and/or a series of samples representing different variances in the reference genes.

In one embodiment, the kit provides two or more primer pairs, each pair capable of amplifying a different region of the reference (ERα) gene (each region a site of potential variance) thereby providing a kit for analysis of expression of several gene variances in a biological sample in one reaction or several parallel reactions.

Primers in the kits may be labelled, for example fluorescently labelled, to facilitate detection of the amplification products and consequent analysis of the nucleic acid variances. The kit may also allow for more than one variance to be detected in one analysis. A combination kit will therefore comprise of primers capable of amplifying different segments of the reference gene. The primers may be differentially labelled, for example using different fluorescent labels, so as to differentiate between the variances.

In another aspect, the specification provides a method of treating a patient suffering from cancer comprising: determining the mutant or wild type status of the ERα gene in the patient's tumour cells and if the ERα gene is mutant, administering to the patient an effective amount of a compound of Formula (I), (IA), (IB), (IC) or (ID).

As used herein, the terms “effective” and “effectiveness” includes both pharmacological effectiveness and physiological safety. Pharmacological effectiveness refers to the ability of the treatment to result in a desired biological effect in the patient. Physiological safety refers to the level of toxicity, or other adverse physiological effects at the cellular, organ and/or organism level (often referred to as side-effects) resulting from administration of the treatment. “Less effective” means that the treatment results in a therapeutically significant lower level of pharmacological effectiveness and/or a therapeutically greater level of adverse physiological effects.

According to another aspect of the specification there is provided the use of a compound of Formula (I), (IA), (IB), (IC) or (ID), or a pharmaceutically acceptable salt thereof, to treat a cancer patient whose tumour cells have been identified as possessing a mutant ERα gene.

According to another aspect of the specification there is provided a compound of Formula (I), (IA), (IB), (IC) or (ID), or a pharmaceutically acceptable salt thereof, for treating cancers with tumour cells identified as harbouring mutant ERα gene.

According to another aspect of the specification there is provided a method of treating cancers with tumour cells identified as harbouring mutant ERα gene comprising administering an effective amount of a compound of Formula (I), (IA), (IB), (IC) or (ID), or a pharmaceutically acceptable salt thereof.

In still further embodiments, the specification relates to a pharmaceutical composition comprising a compound of Formula (I), (IA), (IB), (IC) or (ID), for use in the prevention and treatment of cancer with tumour cells identified as harbouring a mutant ERα gene.

For all the aspects above, mutant forms of ERα determined/identified are at all positions across the gene.

For all the aspects above, using tumours such as breast cancer as an example, particular mutant forms of ERα determined/identified are those at positions Ser463Pro, Val543Glu, Leu536Arg, Tyr537Ser, Tyr537Asn and Asp538Gly.

DESCRIPTION OF DRAWINGS

FIG. 1 shows the X-Ray Powder Diffraction Pattern for Form A of the 2-methoxybenzoate salt of N-(2-((5-((1R,3R)-2-(2,2-difluoroethyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)-4-methoxypyridin-2-yl)oxy)ethyl)-3-fluoropropan-1-amine.

FIG. 2 shows the DSC/TGA Thermogram for Form A of the 2-methoxybenzoate salt of N-(2-((5-((1R,3R)-2-(2,2-difluoroethyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)-4-methoxypyridin-2-yl)oxy)ethyl)-3-fluoropropan-1-amine

EXAMPLES

The specification will now be illustrated in the following Examples in which, generally:

(i) operations were carried out at ambient temperature, i.e. in the range 17 to 25° C. and under an atmosphere of an inert gas such as nitrogen unless otherwise stated;

(ii) evaporations were carried out by rotary evaporation or utilising Genevac equipment or Biotage v10 evaporator in vacuo and work-up procedures were carried out after removal of residual solids by filtration;

(iii) flash chromatography purifications were performed on an automated Teledyne Isco CombiFlash® Rf or Teledyne Isco CombiFlash® Companion® using prepacked RediSep Rf Gold™ Silica Columns (20-40 μm, spherical particles), GraceResolv™ Cartridges (Davisil® silica) or Silicycle cartridges (40-63 μm).

(iv) preparative chromatography was performed on a Gilson prep HPLC instrument with UV collection or via supercritical fluid chromatography performed on a Waters Prep 100 SFC-MS instrument with MS- and UV-triggered collection or a Thar MultiGram III SFC instrument with UV collection;

(v) chiral preparative chromatography was performed on a Gilson instrument with UV collection (233 injector/fraction collector, 333 & 334 pumps, 155 UV detector) or a Varian Prep Star instrument (2×SD1 pumps, 325 UV detector, 701 fraction collector) pump running with Gilson 305 injection;

(vi) yields, where present, are not necessarily the maximum attainable;

(vii) in general, the structures of end-products of the Formula I were confirmed by nuclear magnetic resonance (NMR) spectroscopy; NMR chemical shift values were measured on the delta scale [proton magnetic resonance spectra were determined using a Bruker Avance 500 (500 MHz) or Bruker Avance 400 (400 MHz) instrument]; measurements were taken at ambient temperature unless otherwise specified; the following abbreviations have been used: s, singlet; d, doublet; t, triplet; q, quartet; m, multiplet; dd, doublet of doublets; ddd, doublet of doublet of doublet; dt, doublet of triplets; bs, broad signal

(viii) in general, end-products of the Formula I were also characterised by mass spectroscopy following liquid chromatography (LCMS or UPLC); UPLC was carried out using a Waters UPLC fitted with Waters SQ mass spectrometer (Column temp 40, UV=220-300 nm, Mass Spec=ESI with positive/negative switching) at a flow rate of 1 ml/min using a solvent system of 97% A+3% B to 3% A to 97% B over 1.50 mins (total runtime with equilibration back to starting conditions etc 1.70 min), where A=0.1% formic acid in water (for acid work) or 0.1% ammonia in water (for base work) B=acetonitrile. For acid analysis the column used was Waters Acquity HSS T3 1.8 μm 2.1×50 mm, for base analysis the column used was Waters Acquity BEH 1.7 μm 2.1×50 mm; LCMS was carried out using a Waters Alliance HT (2795) fitted with a Waters ZQ ESCi mass spectrometer and a Phenomenex Gemini-NX (50×2.1 mm 5 μm) column at a flow rate of 1.1 ml/min 95% A to 95% B over 4 min with a 0.5 min hold. The modifier is kept at a constant 5% C (50:50 acetonitrile:water 0.1% formic acid) or D (50:50 acetonitrile:water 0.1% ammonium hydroxide (0.88 SG) depending on whether it is an acidic or basic method.

(ix) ion exchange purification was generally performed using a SCX-2 (Biotage, Propylsulfonic acid functionalized silica. Manufactured using a trifunctional silane. Non end-capped) cartridge.

(x) intermediate purity was assessed by thin layer chromatographic, mass spectral, HPLC (high performance liquid chromatography) and/or NMR analysis;

(xi) RockPhos 3^(rd) Generation Precatalyst was sourced from Strem Chemicals Inc. and from Sigma-Aldrich.

(xii) X-Ray Powder Diffraction (XRPD) Analysis was performed using a Bruker D8 diffractometer, which is commercially available from Bruker AXS Inc™ (Madison, Wis.). The XRPD spectra were obtained by mounting a sample (approximately 10 mg) of the material for analysis on a single silicon crystal wafer mount (e.g., a Bruker silicon zero background X-ray diffraction sample holder) and spreading out the sample into a thin layer with the aid of a microscope slide. The sample was spun at 30 revolutions per minute (to improve counting statistics) and irradiated with X-rays generated by a copper long-fine focus tube operated at 40 kV and 40 mA with a wavelength of 1.5406 angstroms (i.e., about 1.54 angstroms). The sample was exposed for 1 second per 0.02 degree 2-theta increment (continuous scan mode) over the range 5 degrees to 40 degrees 2-theta in theta-theta mode. The running time was ˜17 min for D4 and ˜15.

(xiii) DSC analysis was performed on samples prepared according to standard methods using a Q SERIES™ Q1000 DSC calorimeter available from TA INSTRUMENTS® (New Castle, Del.). A sample (approximately 2 mg) was weighed into an aluminum sample pan and transferred to the DSC. The instrument was purged with nitrogen at 50 mL/min and data collected between 22° C. and 300° C., using a dynamic heating rate of 10° C./minute. Thermal data was analyzed using standard software, e.g., Universal v.4.5A from TA INSTRUMENTS®.

(xiv) Thermogravimetry Analysis (TGA) was performed on samples prepared according to standard methods using a Q SERIES™ Q5000 thermogravimetry analyzer available from TA Instruments INSTRUMENTS® (New Castle, Del.). A sample (approximately 5 mg) was placed into an aluminum sample pan and transferred to the TGA furnace. The instrument was purged with nitrogen at 50 mL/min and data collected between 25° C. and 300° C., using a dynamic heating rate of 10° C./minute. Thermal data was analyzed using standard software, e.g., Universal v.4.5A from TA INSTRUMENTS®.

(xv) the following abbreviations have been used:—

-   -   AcOH acetic acid     -   aq. aqueous     -   n-BuLi n-butyl lithium     -   tBuOH tert-butanol     -   Brettphos         2-(dicyclohexylphosphino)3,6-dimethoxy-2′,4′,6′-triisopropyl-1,1′-biphenyl     -   Brettphos 3^(rd) Generation Precatalyst         [(2-Di-cyclohexylphosphino-3,6-dimethoxy-2′,4′,6′-triisopropyl-1,1′-biphenyl)-2-(2′-amino-1,1′-biphenyl)]palladium(II)         methanesulfonate     -   CDCl₃ deutero-chloroform     -   Conc. concentrated     -   DCM dichloromethane     -   DEAD diethylazodicarboxylate     -   DIPEA diisopropylethylamine     -   DMA N,N-dimethylacetamide     -   DMAP dimethylaminopyridine     -   DME dimethoxyethane     -   DMF N,N-dimethylformamide     -   DMSO dimethyl sulphoxide     -   EtOH ethanol     -   EtOAc ethyl acetate     -   HATU         1-[bis(dimethylamino)methylene]-1H-1,2,3-triazolo[4,5-b]pyridinium         3-oxide hexafluorophosphate     -   HPLC high performance liquid chromatography     -   IPA isopropyl alcohol     -   MeCN acetonitrile     -   MeOH methanol     -   RockPhos 3rd Generation [(2-Di-tert-butylphosphino-3-methoxy-6-     -   Precatalyst         methyl-2′,4′,6′-triisopropyl-1,1′-biphenyl)-2-(2-aminobiphenyl)]palladium(II)         methanesulfonate     -   rt/RT room temperature     -   Ruphos 2-dicyclohexylphosphino-2′,6′-diisopropoxybiphenyl     -   sat. saturated     -   SFC supercritical fluid chromatography     -   sol. solution     -   TBDMS tert-butyldimethylsilyl     -   THF tetrahydrofuran

Example 1 3,3-difluoro-N-(2-(4-((1R,3R)-2-isobutyl-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)phenoxy)ethyl)propan-1-amine

3,3-Difluoropropan-1-amine hydrochloride (36 mg, 0.27 mmol) was added to a stirred mixture of potassium carbonate (94 mg, 0.68 mmol) and (1R,3R)-1-(4-(2-bromoethoxy)phenyl)-2-isobutyl-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole (60 mg, 0.14 mmol) in acetonitrile (1.5 mL) at 21° C. under nitrogen. The resulting mixture was stirred at 82° C. for 5 hours. The reaction mixture was cooled and diluted with DCM. The solids were removed by filtration and the filtrate was concentrated under reduced pressure. The crude product was purified by flash silica chromatography, elution gradient 0 to 5% MeOH in DCM. Product containing fractions were evaporated to dryness to afford 3,3-difluoro-N-(2-(4-((1R,3R)-2-isobutyl-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)phenoxy)ethyl)propan-1-amine (17 mg, 28%) as a yellow gum. ¹H NMR (500 MHz, CDCl₃, 27° C.) 0.78 (3H, d), 0.91 (3H, d), 1.07 (3H, d), 1.76 (1H, dp), 1.96-2.22 (3H, m), 2.32 (1H, dd), 2.59 (1H, ddd), 2.80-2.95 (3H, m), 2.95-3.06 (2H, m), 3.26-3.43 (1H, m), 4.05 (2H, t), 4.64 (1H, s), 5.95 (1H, tt), 6.78-6.87 (2H, m), 7.10 (2H, dtd), 7.16-7.24 (3H, m), 7.42 (1H, s), 7.49-7.54 (1H, m). m/z: ES+ [M+H]+ 456.

Preparation of (1R,3R)-1-(4-(2-bromoethoxy)phenyl)-2-isobutyl-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole

Diisopropyl (E)-diazene-1,2-dicarboxylate (1.18 ml, 5.98 mmol) was added dropwise to a stirred solution of 4-((1R,3R)-2-isobutyl-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)phenol (1.00 g, 2.99 mmol), 2-bromoethan-1-ol (0.530 ml, 7.47 mmol) and triphenylphosphine (1.57 g, 5.98 mmol) in DCM (24 ml) at 5° C. The resulting mixture was stirred at 5° C. for 30 minutes then at 21° C. for 16 hours. DCM (15 mL) and water (25 mL) were added and the layers were separated. The aqueous layer was extracted with DCM (2×25 mL). The combined organics were washed with brine (25 mL), dried (Na₂SO₄), filtered and concentrated to give the crude material that was purified by flash silica chromatography, elution gradient 0 to 30% EtOAc in heptane. Product containing fractions were evaporated to dryness to afford (1R,3R)-1-(4-(2-bromoethoxy)phenyl)-2-isobutyl-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole (0.91 g, 69%) as a yellow solid. ¹H NMR (500 MHz, CDCl₃, 27° C.) 0.78 (3H, d), 0.91 (3H, d), 1.07 (3H, d), 1.76 (1H, dt), 2.13 (1H, dd), 2.32 (1H, dd), 2.59 (1H, ddd), 2.88 (1H, dd), 3.26-3.42 (1H, m), 3.63 (2H, t), 4.27 (2H, t), 4.65 (1H, s), 6.80-6.86 (2H, m), 7.06-7.15 (2H, m), 7.18-7.24 (3H, m), 7.40 (1H, s), 7.48-7.55 (1H, m). m/z: ES+ [M+H]+ 441.

Preparation of 4-((1R,3R)-2-isobutyl-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)phenol

Aqueous hydrogen peroxide (35%; 1.30 mL, 15.1 mmol) was added dropwise to a stirred solution of (1R,3R)-2-isobutyl-3-methyl-1-(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl)-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole (2.92 g, 6.56 mmol) and aqueous sodium hydroxide (2M; 3.28 mL, 6.56 mmol) in THF (35 mL) at 5° C. under air. The resulting mixture was stirred at 5° C. for 5 minutes. The mixture was diluted with water (50 mL) and DCM (50 mL). The layers were separated and the aqueous layer was extracted with DCM (2×50 mL). The combined organic layers were dried over sodium sulfate, filtered, and concentrated under reduced pressure. The resulting yellow solid was purified by flash silica chromatography, elution gradient 0 to 50% EtOAc in heptane. Product fractions were evaporated to dryness to afford 4-((1R,3R)-2-isobutyl-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)phenol (1.50 g, 68%) as a white solid. ¹H NMR (500 MHz, DMSO-d₆, 27° C.) 0.78 (3H, d), 0.93 (3H, d), 1.02 (3H, d), 1.73-1.83 (1H, m), 2.10 (1H, dd), 2.27 (1H, dd), 2.43-2.48 (1H, m), 2.65 (1H, dd), 3.15 (1H, s), 4.67 (1H, s), 6.67 (2H, d), 6.90-6.96 (1H, m), 6.96-7.02 (3H, m), 7.22 (1H, d), 7.38 (1H, d), 9.23 (1H, s), 10.51 (1H, s). m/z: ES+ [M+H]+ 335.

Preparation of (1R,3R)-2-isobutyl-3-methyl-1-(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl)-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole

Acetic acid (6.67 mL) was added to a solution of (R)—N-(1-(1H-indol-3-yl)propan-2-yl)-2-methylpropan-1-amine (3.00 g, 13.0 mmol) and 4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)benzaldehyde (3.02 g, 13.0 mmol) in toluene (60 mL). The resulting mixture was heated at 90° C. for 16 hours. The mixture was concentrated under reduced pressure and the crude product was purified by flash silica chromatography, elution gradient 0 to 50% EtOAc in heptane. Product fractions were evaporated to dryness to afford (1R,3R)-2-isobutyl-3-methyl-1-(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl)-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole (3.51 g, 60%) as a yellow foam. ¹H NMR (500 MHz, DMSO-d₆, 27° C.) 0.79 (3H, d), 0.93 (3H, d), 1.02 (3H, d), 1.27 (11H, s), 1.75-1.88 (1H, m), 2.10 (1H, dd), 2.29-2.35 (1H, m), 2.68 (1H, dd), 3.08-3.19 (1H, m), 4.77 (1H, s), 6.94 (1H, td), 6.97-7.05 (1H, m), 7.24 (3H, t), 7.40 (1H, d), 7.61 (2H, d), 7.88 (2H, q), 10.53 (1H, s). m/z: ES+ [M+H]+ 445.

Preparation of (R)—N-(1-(1H-indol-3-yl)propan-2-yl)-2-methylpropan-1-amine

Sodium triacetoxyborohydride (10.3 g, 48.5 mmol) was added in one portion to (R)-1-(1H-indol-3-yl)propan-2-amine (6.65 g, 38.1 mmol) and isobutyraldehyde (3.16 mL, 34.7 mmol) in THF (200 mL) at room temperature under nitrogen. The reaction was stirred at room temperature for 5 hrs and then stored in the refrigerator over the weekend. The reaction was then quenched with 150 mL saturated aqueous sodium bicarbonate, extracted with EtOAc (2×150 mL), and the combined organic layers were dried over sodium sulfate, filtered, and concentrated under reduced pressure. The resulting residue was adsorbed onto silica and purified by flash silica chromatography, elution gradient 0 to 20% MeOH in DCM, to afford (R)—N-(1-(1H-indol-3-yl)propan-2-yl)-2-methylpropan-1-amine (6.50 g, 81%) as an off-white solid. ¹H NMR (300 MHz, DMSO-d₆, 27° C.) 0.81 (6H, d), 0.96 (3H, d), 1.45-1.70 (1H, m), 2.31-2.44 (2H, m), 2.53-2.68 (1H, m), 2.74-2.96 (2H, m), 6.86-7.09 (2H, m), 7.12 (1H, d), 7.32 (1H, d), 7.43-7.57 (1H, m), 10.65-10.86 (1H, m). NH not visible. m/z: ES+ [M+H]+ 231.

Example 2 3-fluoro-N-(2-(4-((1R,3R)-2-isobutyl-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)phenoxy)ethyl)propan-1-amine

3-Fluoropropan-1-amine hydrochloride (31 mg, 0.27 mmol) was added to (1R,3R)-1-(4-(2-bromoethoxy)phenyl)-2-isobutyl-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole (60 mg, 0.14 mmol) and potassium carbonate (126 mg, 0.91 mmol) in acetonitrile (1.5 mL) at 21° C. under nitrogen. The resulting mixture was stirred at 82° C. for 16 hours. The reaction mixture was cooled and diluted with DCM. The solids were removed by filtration and the filtrate was concentrated under reduced pressure. The crude product was purified by flash silica chromatography, elution gradient 0 to 5% MeOH in DCM. Pure fractions were evaporated to dryness to afford 3-fluoro-N-(2-(4-((1R,3R)-2-isobutyl-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)phenoxy)ethyl)propan-1-amine (22 mg, 37%) as a white solid. ¹H NMR (500 MHz, CDCl₃, 27° C.) 0.78 (3H, d), 0.90 (3H, d), 1.07 (3H, d), 1.61 (1H, s), 1.76 (1H, dt), 1.84-1.98 (2H, m), 2.13 (1H, dd), 2.31 (1H, dd), 2.59 (1H, ddd), 2.82 (2H, t), 2.89 (1H, dd), 2.97-3.05 (2H, m), 3.29-3.40 (1H, m), 4.06 (2H, t), 4.49 (1H, t), 4.59 (1H, t), 4.64 (1H, s), 6.77-6.88 (2H, m), 7.05-7.16 (2H, m), 7.16-7.25 (3H, m), 7.42 (1H, s), 7.49-7.56 (1H, m). m/z: ES+ [M+H]+ 438.

Example 3 N-(2-(3,5-difluoro-4-((1R,3R)-2-(2-fluoro-2-methylpropyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)phenoxy)ethyl)-3,3-difluoropropan-1-amine

3,3-Difluoropropan-1-amine hydrochloride (106 mg, 0.81 mmol) was added to (1R,3R)-1-(4-(2-bromoethoxy)-2,6-difluorophenyl)-2-(2-fluoro-2-methylpropyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole (200 mg, 0.40 mmol) and potassium carbonate (126 mg, 0.91 mmol) in acetonitrile (5 mL) at 21° C. under nitrogen. The resulting mixture was stirred at 82° C. for 16 hours. The reaction mixture was cooled and diluted with DCM. The solids were removed by filtration and the filtrate was concentrated under reduced pressure. The crude product was purified by flash silica chromatography, elution gradient 0 to 3% MeOH in DCM. Product containing fractions were evaporated to dryness to afford N-(2-(3,5-difluoro-4-((1R,3R)-2-(2-fluoro-2-methylpropyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)phenoxy)ethyl)-3,3-difluoropropan-1-amine (105 mg, 51%) as a white solid. ¹H NMR (500 MHz, CDCl₃, 27° C.) 1.10 (3H, d), 1.20 (6H, dd), 1.54 (1H, s), 1.98-2.17 (2H, m), 2.39 (1H, dd), 2.60 (1H, dd), 2.87 (3H, t), 2.97-3.04 (2H, m), 3.09 (1H, d), 3.70 (1H, s), 4.02 (2H, t), 5.19 (1H, s), 5.96 (1H, t), 6.36-6.46 (2H, m), 7.06-7.15 (2H, m), 7.20-7.25 (1H, m), 7.39 (1H, s), 7.51 (1H, dd). m/z: ES− [M−H]− 508.

Preparation of (1R,3R)-1-(4-(2-bromoethoxy)-2,6-difluorophenyl)-2-(2-fluoro-2-methylpropyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole

Diisopropyl (E)-diazene-1,2-dicarboxylate (1.52 ml, 7.72 mmol) was added dropwise to a stirred solution of 3,5-difluoro-4-((1R,3R)-2-(2-fluoro-2-methylpropyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)phenol (1.50 g, 3.86 mmol), 2-bromoethan-1-ol (0.684 ml, 9.65 mmol) and triphenylphosphine (2.03 g, 7.72 mmol) in DCM (30 ml) at 5° C. The resulting mixture was stirred at 5° C. for 30 minutes then at 21° C. for 16 hours. DCM (15 mL) and water (25 mL) were added and the layers were separated. The aqueous layer was extracted with DCM (2×25 mL). The combined organics were washed with brine (25 mL), dried (Na₂SO₄), filtered and concentrated to give the crude product. The crude product was purified by flash silica chromatography, elution gradient 0 to 20% EtOAc in heptane. Product containing fractions were evaporated to dryness to afford (1R,3R)-1-(4-(2-bromoethoxy)-2,6-difluorophenyl)-2-(2-fluoro-2-methylpropyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole (1.35 g, 71%) as a pale yellow solid. ¹H NMR (500 MHz, CDCl₃, 27° C.) 1.10 (3H, d), 1.18 (6H, d), 2.39 (1H, dd), 2.60 (1H, ddd), 2.86 (1H, dd), 3.08 (1H, dd), 3.62 (2H, t), 3.64-3.72 (1H, m), 4.24 (2H, t), 5.20 (1H, s), 6.37-6.47 (2H, m), 7.07-7.15 (2H, m), 7.20-7.24 (1H, m), 7.39 (1H, s), 7.49-7.56 (1H, m). m/z: ES− [M−H]− 495.

Preparation of 3,5-difluoro-4-((1R,3R)-2-(2-fluoro-2-methylpropyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)phenol

Acetic acid (0.684 mL) was added to (R)—N-(1-(1H-indol-3-yl)propan-2-yl)-2-fluoro-2-methylpropan-1-amine (1.20 g, 1.58 mmol) (see WO2014/191726) and 2,6-difluoro-4-hydroxybenzaldehyde (0.250 g, 1.58 mmol) in toluene (6 mL). The resulting solution was stirred at 80° C. for 16 hours. The reaction mixture was diluted with EtOAc (50 mL) and washed with saturated NaHCO₃ (50 mL). The organic layer was dried with Na₂SO₄, filtered and evaporated to afford the crude product which was purified by flash silica chromatography, elution gradient 0 to 10% EtOAc in DCM. Product containing fractions were evaporated to dryness to afford 3,5-difluoro-4-((1R,3R)-2-(2-fluoro-2-methylpropyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)phenol (0.465 g, 76%) as a yellow foam. ¹H NMR (500 MHz, DMSO, 27° C.) 1.02 (3H, d), 1.09-1.21 (6H, m), 2.22-2.38 (1H, m), 2.50-2.56 (1H, m), 2.74-2.93 (2H, m), 3.50 (1H, d), 5.07 (1H, s), 6.37 (2H, d), 6.95 (2H, dtd), 7.17 (1H, d), 7.37 (1H, d), 10.29 (1H, s), 10.48 (1H, s). m/z: ES+ [M+H]+ 389.

Example 4 N-(2-(3,5-difluoro-4-((1R,3R)-2-(2-fluoro-2-methylpropyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)phenoxy)ethyl)-3-fluoropropan-1-amine

3-Fluoropropan-1-amine hydrochloride (117 mg, 1.03 mmol) was added to (1R,3R)-1-(4-(2-bromoethoxy)-2,6-difluorophenyl)-2-(2-fluoro-2-methylpropyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole (255 mg, 0.515 mmol) and potassium carbonate (356 mg, 2.56 mmol) in acetonitrile (5 mL) at 21° C. under nitrogen. The resulting mixture was stirred at 82° C. for 16 hours. The reaction mixture was cooled and diluted with DCM. The solids were removed by filtration and the filtrate was concentrated under reduced pressure. The crude product was purified by flash silica chromatography, elution gradient 0 to 3% MeOH in DCM. Product containing fractions were evaporated to dryness to afford N-(2-(3,5-difluoro-4-((1R,3R)-2-(2-fluoro-2-methylpropyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)phenoxy)ethyl)-3-fluoropropan-1-amine (175 mg, 69%) as a white solid. ¹H NMR (500 MHz, CDCl₃, 27° C.) 1.10 (3H, d), 1.20 (6H, dd), 1.50 (1H, s), 1.90 (2H, dddd), 2.38 (1H, dd), 2.60 (1H, dd), 2.79-2.91 (3H, m), 2.97-3.04 (2H, m), 3.09 (1H, dd), 3.68 (1H, d), 4.02 (2H, t), 4.50 (1H, t), 4.59 (1H, t), 5.19 (1H, s), 6.33-6.48 (2H, m), 7.06-7.14 (2H, m), 7.20-7.24 (1H, m), 7.39 (1H, s), 7.49-7.55 (1H, m). m/z: ES− [M−H]− 490.

Example 5 N-(2-(3,5-difluoro-4-((1R,3R)-2-((3-fluorooxetan-3-yl)methyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)phenoxy)ethyl)-3-fluoropropan-1-amine

3-Fluoropropan-1-amine hydrochloride (312 mg, 2.75 mmol) was added to (1R,3R)-1-(4-(2-bromoethoxy)-2,6-difluorophenyl)-2-((3-fluorooxetan-3-yl)methyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole (700 mg, 1.37 mmol) and potassium carbonate (947 mg, 6.85 mmol) in acetonitrile (10 mL) at 21° C. under nitrogen. The resulting mixture was stirred at 82° C. for 16 hours. The reaction mixture was cooled, filtered and the solid washed with DCM. The filtrate was concentrated in vacuo. The crude product was purified by preparative HPLC (Waters XSelect CSH C18 column, 5μ silica, 30 mm diameter, 100 mm length), using decreasingly polar mixtures of water (containing 1% NH₃) and MeCN as eluents. Fractions containing the desired compound were evaporated to dryness to afford N-(2-(3,5-difluoro-4-((1R,3R)-2-((3-fluorooxetan-3-yl)methyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)phenoxy)ethyl)-3-fluoropropan-1-amine (350 mg, 50%) as a white solid. ¹H NMR (500 MHz, CDCl₃, 27° C.) 1.16 (3H, d), 1.53 (1H, s), 1.90 (2H, dddd), 2.56-2.66 (1H, m), 2.77-3.07 (6H, m), 3.17 (1H, dd), 3.51-3.61 (1H, m), 4.02 (2H, t), 4.34 (1H, dd), 4.42-4.53 (2H, m), 4.59 (1H, t), 4.68 (2H, td), 5.25 (1H, s), 6.37-6.49 (2H, m), 7.05-7.17 (2H, m), 7.22-7.25 (1H, m), 7.44-7.55 (2H, m). m/z: ES+ [M+H]+ 506

Preparation of (1R,3R)-1-(4-(2-bromoethoxy)-2,6-difluorophenyl)-2-((3-fluorooxetan-3-yl)methyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole

Diisopropyl (E)-diazene-1,2-dicarboxylate (0.890 mL, 4.52 mmol) was added dropwise to a stirred solution of 3,5-difluoro-4-((1R,3R)-2-((3-fluorooxetan-3-yl)methyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)phenol (910 mg, 2.26 mmol), 2-bromoethan-1-ol (0.401 mL, 5.65 mmol) and triphenylphosphine (1.19 g, 4.52 mmol) in DCM (20 mL) at 5° C. The resulting mixture was stirred at 5° C. for 30 minutes followed by 21° C. for 16 hours. DCM (15 mL) and water (25 mL) were added and the layers were separated. The aqueous layer was extracted with DCM (2×25 mL). The combined organics were washed with brine (25 mL), dried (Na₂SO₄) and concentrated in vacuo to give the crude product. The crude product was purified by flash silica chromatography, elution gradient 0 to 30% EtOAc in heptane. Pure fractions were evaporated to dryness to afford (1R,3R)-1-(4-(2-bromoethoxy)-2,6-difluorophenyl)-2-((3-fluorooxetan-3-yl)methyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole (1.00 g, 87%) as a white solid. ¹H NMR (500 MHz, CDCl₃, 27° C.) 1.16 (3H, d), 2.61 (1H, ddd), 2.81-3.03 (2H, m), 3.17 (1H, dd), 3.53 (1H, dt), 3.61 (2H, t), 4.23 (2H, td), 4.34 (1H, dd), 4.49 (1H, dd), 4.68 (2H, td), 5.26 (1H, s), 6.36-6.47 (2H, m), 7.05-7.16 (2H, m), 7.21-7.24 (1H, m), 7.47-7.55 (2H, m). m/z: ES+ [M+H]+ 511

Preparation of 3,5-difluoro-4-((1R,3R)-2-((3-fluorooxetan-3-yl)methyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)phenol

2,6-Difluoro-4-hydroxybenzaldehyde (0.848 g, 5.36 mmol) was added to a solution of (R)—N-((3-fluorooxetan-3-yl)methyl)-1-(1H-indol-3-yl)propan-2-amine (1.34 g, 5.11 mmol) in toluene (23 mL)/acetic acid (2.55 mL) and the reaction was stirred at 80° C. overnight. After cooling, the volatiles were evaporated and the crude product was purified by ion exchange chromatography using an SCX column. The desired product was eluted from the column using 1M NH₃/MeOH and pure fractions were evaporated to dryness. The resulting residue was purified by flash silica chromatography, elution gradient 0 to 40% EtOAc in heptane. Pure fractions were evaporated to dryness to afford 3,5-difluoro-4-((1R,3R)-2-((3-fluorooxetan-3-yl)methyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)phenol (1.25 g, 61%) as a cream solid. ¹H NMR (500 MHz, CDCl₃, 27° C.) 1.16 (3H, d), 2.62 (1H, ddd), 2.81-3.03 (2H, m), 3.18 (1H, dd), 3.52-3.61 (1H, m), 4.36 (1H, dd), 4.47 (1H, dd), 4.64-4.78 (2H, m), 5.24 (1H, s), 5.73 (1H, s), 6.27-6.37 (2H, m), 7.07-7.18 (2H, m), 7.22-7.25 (1H, m), 7.47 (1H, s), 7.51 (1H, dd). m/z: ES− [M−H]− 401.

Preparation of (R)—N-((3-fluorooxetan-3-yl)methyl)-1-(1H-indol-3-yl)propan-2-amine

A solution of (3-fluorooxetan-3-yl)methyl trifluoromethanesulfonate (431 mg, 1.81 mmol) in DCM (3 mL) was added dropwise to a stirred solution of (R)-1-(1H-indol-3-yl)propan-2-amine (287 mg, 1.65 mmol) and diisopropylethylamine (0.345 mL, 1.97 mmol) in DCM (7 mL) at ambient temperature. The reaction was stirred for 8 hours and then diluted with DCM and washed with water. The phases were separated, and the organic layer was dried over MgSO₄, filtered, and concentrated under reduced pressure. The resulting residue was purified by flash silica chromatography, elution gradient 30 to 100% EtOAc in hexanes. Product fractions were combined and concentrated under reduced pressure to afford (R)—N-((3-fluorooxetan-3-yl)methyl)-1-(1H-indol-3-yl)propan-2-amine (384 mg, 89%) as a colorless gum. ¹H NMR (300 MHz, CDCl₃, 27° C.) 1.12 (3H, d), 2.82 (2H, dd), 2.95-3.07 (3H, m), 3.12 (1H, t), 4.49 (2H, ddd), 4.67 (1H, dd), 4.70-4.78 (1H, m), 6.92 (1H, d), 7.05-7.14 (1H, m), 7.18 (1H, td), 7.29 (1H, d), 7.59 (1H, d), 8.34 (1H, br s). m/z: ES+ [M+H]+ 263.

Preparation of (3-fluorooxetan-3-yl)methyl trifluoromethanesulfonate

2,6-Lutidine (0.441 mL, 3.79 mmol) was added to a stirred solution of (3-fluorooxetan-3-yl)methanol (335 mg, 3.16 mmol) in anhydrous DCM (15 mL) at −10° C. Trifluoromethanesulfonic anhydride (0.560 mL, 3.32 mmol) was then added dropwise via syringe over 3 minutes, and the reaction was allowed to stir at −10° C. for 40 minutes. The cooling bath was removed, and the solution was washed successively with cold aqueous HCl (1 N; 2×5 mL) and saturated aqueous NaHCO₃ (2×5 mL), then dried over MgSO₄, filtered and concentrated under reduced pressure. Drying under vacuum afforded (3-fluorooxetan-3-yl)methyl trifluoromethanesulfonate (431 mg, 57%) as a pale yellow oil, which was used without further purification. ¹H NMR (300 MHz, CDCl₃, 27° C.) 4.53-4.67 (2H, m), 4.79-4.95 (4H, m).

Alternative Route to Example 5 N-(2-(3,5-difluoro-4-((1R,3R)-2-((3-fluorooxetan-3-yl)methyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)phenoxy)ethyl)-3-fluoropropan-1-amine

3-Fluoropropan-1-amine hydrochloride (43.3 mg, 0.38 mmol) was added to a suspension of 2-(3,5-difluoro-4-((1R,3R)-2-((3-fluorooxetan-3-yl)methyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)phenoxy)ethyl methanesulfonate (100 mg, 0.19 mmol), potassium carbonate (79 mg, 0.57 mmol) and potassium iodide (31.6 mg, 0.19 mmol) in acetonitrile (1. mL). The mixture was heated to 100° C. and stirred at 100° C. for 5 hours. After cooling, the mixture was diluted with EtOAc and washed with water. The aqueous phase was extracted with EtOAc and the combined organics were evaporated. The crude product was purified by flash silica chromatography, elution gradient 0 to 20% MeOH in EtOAc. Product containing fractions were evaporated to dryness to afford N-(2-(3,5-difluoro-4-((1R,3R)-2-((3-fluorooxetan-3-yl)methyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)phenoxy)ethyl)-3-fluoropropan-1-amine (46.0 mg, 48%) as a colourless solid. ¹H NMR (500 MHz, CDCl₃, 27° C.) 1.16 (3H, d), 1.53 (1H, s), 1.90 (2H, dddd), 2.56-2.66 (1H, m), 2.77-3.07 (6H, m), 3.17 (1H, dd), 3.51-3.61 (1H, m), 4.02 (2H, t), 4.34 (1H, dd), 4.42-4.53 (2H, m), 4.59 (1H, t), 4.68 (2H, td), 5.25 (1H, s), 6.37-6.49 (2H, m), 7.05-7.17 (2H, m), 7.22-7.25 (1H, m), 7.44-7.55 (2H, m). m/z: ES+ [M+H]+ 506

Preparation of 2-(3,5-difluoro-4-((1R,3R)-2-((3-fluorooxetan-3-yl)methyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)phenoxy)ethyl methanesulfonate

Methanesulfonyl chloride (0.044 ml, 0.57 mmol) was added to a solution of 2-(3,5-difluoro-4-((1R,3R)-2-((3-fluorooxetan-3-yl)methyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)phenoxy)ethan-1-ol (0.230 g, 0.52 mmol) and triethylamine (0.086 ml, 0.62 mmol) in DCM (2.5 mL) and the reaction was stirred at room temperature for 2 hours. The reaction was diluted with DCM and washed with water. The aqueous was extracted with DCM, and the combined organics were dried and evaporated to afford 2-(3,5-difluoro-4-((1R,3R)-2-((3-fluorooxetan-3-yl)methyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)phenoxy)ethyl methanesulfonate (0.280 g, 100%) as a yellow solid, which was used directly. ¹H NMR (500 MHz, CDCl₃, 27° C.) 1.16 (3H, d), 2.56-2.67 (1H, m), 2.84-3.03 (2H, m), 3.09 (3H, s), 3.15-3.24 (1H, m), 3.54 (1H, d), 4.16-4.25 (2H, m), 4.34 (1H, dd), 4.49 (1H, dd), 4.55 (2H, dd), 4.62-4.76 (2H, m), 5.27 (1H, s), 6.44 (2H, d), 7.07-7.16 (2H, m), 7.23-7.28 (1H, m), 7.45-7.54 (2H, m). m/z: ES+ [M+H]+ 525

Preparation of 2-(3,5-difluoro-4-((1R,3R)-2-((3-fluorooxetan-3-yl)methyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)phenoxy)ethan-1-ol

Tetrabutylammonium fluoride (1.0M in THF, 1.083 mL, 1.08 mmol) was added to a mixture of (1R,3R)-1-(4-(2-((tert-butyldimethylsilyl)oxy)ethoxy)-2,6-difluorophenyl)-2-((3-fluorooxetan-3-yl)methyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole (405 mg, 0.72 mmol) in THF (3 mL) at 21° C. under nitrogen. The resulting mixture was stirred at 21° C. for 2 hours. The mixture was concentrated under reduced pressure to give the crude product that was purified by flash silica chromatography, elution gradient 0 to 100% EtOAc in heptane. Product containing fractions were evaporated to dryness to afford 2-(3,5-difluoro-4-((1R,3R)-2-((3-fluorooxetan-3-yl)methyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)phenoxy)ethan-1-ol (230 mg, 71%) as a pale yellow solid. ¹H NMR (500 MHz, CDCl₃, 27° C.) 1.16 (3H, d), 1.92 (1H, t), 2.62 (1H, dd), 2.91 (1H, dd), 3.00 (1H, dd), 3.18 (1H, dd), 3.50-3.60 (1H, m), 3.93-3.99 (2H, m), 4.02-4.07 (2H, m), 4.34 (1H, dd), 4.48 (1H, dd), 4.68 (2H, td), 5.26 (1H, s), 6.42-6.48 (2H, m), 7.08-7.16 (2H, m), 7.24 (1H, dd), 7.47 (1H, d), 7.51 (1H, d). m/z: ES+ [M+H]+ 447.

Preparation of (1R,3R)-1-(4-(2-((tert-butyldimethylsilyl)oxy)ethoxy)-2,6-difluorophenyl)-2-((3-fluorooxetan-3-yl)methyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole

2-((Tert-butyldimethylsilyl)oxy)ethan-1-ol (331 mg, 1.88 mmol) and RockPhos 3rd Generation Precatalyst (35.0 mg, 0.04 mmol) were added to a suspension of (1R,3R)-1-(4-bromo-2,6-difluorophenyl)-2-((3-fluorooxetan-3-yl)methyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole (485 mg, 1.04 mmol) and cesium carbonate (847 mg, 2.61 mmol) in degassed toluene (6 mL). The mixture was heated to 90° C. and stirred at 90° C. for 16 hours. After cooling, the reaction was diluted with EtOAc and water. The layers were separated and aqueous layer was extracted with EtOAc. The combined organics were dried and evaporated, and the crude product was purified by flash silica chromatography, elution gradient 0 to 50% EtOAc in heptane. Product containing fractions were evaporated to dryness to afford (1R,3R)-1-(4-(2-((tert-butyldimethylsilyl)oxy)ethoxy)-2,6-difluorophenyl)-2-((3-fluorooxetan-3-yl)methyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole (406 mg, 70%) as a pale yellow oil. ¹H NMR (500 MHz, CDCl₃, 27° C.) 0.09 (6H, s), 0.91 (9H, s), 1.16 (3H, d), 2.61 (1H, dd), 2.84-3.03 (2H, m), 3.17 (1H, dd), 3.54 (1H, d), 3.95 (2H, td), 4.00 (2H, t), 4.35 (1H, dd), 4.48 (1H, dd), 4.61-4.75 (2H, m), 5.25 (1H, s), 6.43 (2H, d), 7.07-7.16 (2H, m), 7.22-7.26 (1H, m), 7.47 (1H, s), 7.51 (1H, d). m/z: ES+ [M+H]+ 561.

Preparation of (1R,3R)-1-(4-bromo-2,6-difluorophenyl)-2-((3-fluorooxetan-3-yl)methyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole

4-Bromo-2,6-difluorobenzaldehyde (3.01 g, 13.61 mmol) was added to a solution of (R)—N-((3-fluorooxetan-3-yl)methyl)-1-(1H-indol-3-yl)propan-2-amine (3.40 g, 12.96 mmol) in toluene (46.7 mL) and acetic acid (5.18 mL) and the reaction was heated to 80° C. and stirred at 80° C. for 4 hours. After cooling, the volatiles were evaporated, then the residue was dissolved in DCM and washed with saturated aqueous NaHCO₃. The aqueous was extracted with DCM, then dried and evaporated. The crude product was purified by ion exchange chromatography, using an SCX column. The desired product was eluted from the column using 1M NH₃/MeOH and product containing fractions were evaporated to dryness. The resulting product was purified by flash silica chromatography, elution gradient 0 to 40% EtOAc in heptane. Product containing fractions were evaporated to dryness to afford (1R,3R)-1-(4-bromo-2,6-difluorophenyl)-2-((3-fluorooxetan-3-yl)methyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole (4.87 g, 81%) as a colourless solid. ¹H NMR (500 MHz, CDCl₃, 27° C.) 1.18 (3H, d), 2.63 (1H, ddd), 2.85-3.00 (2H, m), 3.20 (1H, dd), 3.44-3.53 (1H, m), 4.34 (1H, dd), 4.53 (1H, dd), 4.70 (2H, ddd), 5.32 (1H, s), 7.03-7.08 (2H, m), 7.09-7.13 (1H, m), 7.13-7.18 (1H, m), 7.23-7.26 (1H, m), 7.49 (1H, s), 7.50-7.55 (1H, m). m/z: ES+ [M+H]+ 465.

Example 6 N-(2-(3,5-difluoro-4-((1R,3R)-2-((1-fluorocyclopropyl)methyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)phenoxy)ethyl)-3-fluoropropan-1-amine

Trifluoroacetic acid (0.50 mL, 6.5 mmol) was added to a solution of tert-butyl (2-(3,5-difluoro-4-((1R,3R)-2-((1-fluorocyclopropyl)methyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)phenoxy)ethyl)(3-fluoropropyl)carbamate (0.42 g, 0.70 mmol) in DCM (5 mL). The mixture was stirred at room temperature for 1 hour. The reaction was loaded onto an SCX-2 column and eluted first with MeOH and then ammonia in MeOH (3M). Product fractions were concentrated under reduced pressure, and the resulting residue purified by flash silica chromatography, elution gradient 0 to 10% methanol in DCM, to afford N-(2-(3,5-difluoro-4-((1R,3R)-2-((1-fluorocyclopropyl)methyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)phenoxy)ethyl)-3-fluoropropan-1-amine (0.147 g, 43%) as a colorless film. ¹H NMR (500 MHz, DMSO-d₆) 0.53 (2H, br t), 0.92 (2H, br d), 1.07 (3H, d), 1.64-1.92 (3H, m), 2.57-2.74 (4H, m), 2.79-2.93 (3H, m), 3.06 (1H, dd), 3.50-3.69 (1H, m), 4.04 (2H, t), 4.46 (1H, t), 4.56 (1H, t), 5.18 (1H, s), 6.68 (2H, d), 6.87-7.06 (2H, m), 7.19 (1H, d), 7.40 (1H, d), 10.54 (1H, s). m/z: ES+ [M+H]+ 490.

Preparation of tert-butyl (2-(3,5-difluoro-4-((1R,3R)-2-((1-fluorocyclopropyl)methyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)phenoxy)ethyl)(3-fluoropropyl)carbamate

Diisopropyl (E)-diazene-1,2-dicarboxylate (0.220 mL, 1.13 mmol) was added dropwise to a solution of 3,5-difluoro-4-((1R,3R)-2-((1-fluorocyclopropyl)methyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)phenol (0.365 g, 0.94 mmol), tert-butyl (3-fluoropropyl)(2-hydroxyethyl)carbamate (0.251 g, 1.13 mmol) and triphenylphosphine (0.297 g, 1.13 mmol) in toluene (6 mL). The mixture was stirred at room temperature for 1 hour and then concentrated under reduced pressure. The resulting residue was purified by flash silica chromatography, elution gradient 0 to 70% EtOAc in Hexanes, to afford tert-butyl (2-(3,5-difluoro-4-((1R,3R)-2-((1-fluorocyclopropyl)methyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)phenoxy)ethyl)(3-fluoropropyl)carbamate (0.44 g, 78%) as a light brown gum. ¹H NMR (300 MHz, DMSO-d₆) 0.52 (2H, br dd), 0.82-0.97 (2H, m), 1.06 (3H, d), 1.39 (9H, s), 1.77-1.97 (2H, m), 2.54-2.76 (2H, m), 2.81-3.14 (2H, m), 3.35 (2H, br s), 3.42-3.63 (3H, m), 4.10 (2H, br t), 4.37 (1H, t), 4.53 (1H, t), 5.17 (1H, s), 6.68 (2H, d), 6.84-7.07 (2H, m), 7.18 (1H, d), 7.40 (1H, d), 10.51 (1H, s). m/z: ES+ [M+H]+ 590.

Preparation of 3,5-difluoro-4-((1R,3R)-2-((1-fluorocyclopropyl)methyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)phenol

p-Toluene sulfonic acid (31 mg, 0.16 mmol) was added to a solution of 2,6-difluoro-4-hydroxybenzaldehyde (257 mg, 1.62 mmol) and (R)—N-fluorocyclopropyl)methyl)-1-(1H-indol-3-yl)propan-2-amine (400 mg, 1.62 mmol) in toluene (16 mL) and stirred at 80° C. for 16 hours. The reaction was concentrated under reduced pressure, and the resulting residue was purified by flash silica chromatography, elution gradient 0 to 60% EtOAc in hexanes, to afford 3,5-difluoro-4-((1R,3R)-2-((1-fluorocyclopropyl)methyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)phenol (311 mg, 50%) as a foam solid. ¹H NMR (300 MHz, DMSO-d₆) 0.39-0.58 (2H, m), 0.90 (2H, br d), 1.06 (3H, d), 2.54-2.76 (2H, m), 2.88 (1H, dd), 3.06 (1H, dd), 3.47-3.73 (1H, m), 5.13 (1H, s), 6.39 (2H, d), 6.84-7.09 (2H, m), 7.14-7.28 (1H, m), 7.39 (1H, d), 10.30 (1H, s), 10.50 (1H, s). m/z: ES+ [M+H]+ 387.

Preparation of (R)—N-((1-fluorocyclopropyl)methyl)-1-(1H-indol-3-yl)propan-2-amine

Borane (1.0 M solution in THF, 58.8 mL, 58.8 mmol) was added dropwise to a solution of (R)—N-(1-(1H-indol-3-yl)propan-2-yl)-1-fluorocyclopropane-1-carboxamide (5.1 g, 20 mmol) in THF (5 mL) at room temperature. The reaction was warmed to 65° C. and maintained under these conditions for 6 hours. The reaction was then cooled to room temperature and quenched slowly by dropwise addition of methanol until gas evolution ceased. The mixture was concentrated under reduced pressure, and the resulting residue was dissolved in methanol. This solution was warmed to 65° C. and maintained under these conditions for 6 hours before being cooled to room temperature. After 18 hours, the reaction was concentrated under reduced pressure, and the resulting residue was purified by flash silica chromatography, elution gradient 0 to 90% ethyl acetate to afford (R)—N-((1-fluorocyclopropyl)methyl)-1-(1H-indol-3-yl)propan-2-amine (3.16 g, 66%) as a white solid. ¹H NMR (300 MHz, DMSO-d₆) 0.56-0.70 (2H, m), 0.81-0.95 (2H, m), 0.98 (3H, d), 1.65 (1H, br s), 2.56-2.67 (1H, m), 2.78-3.09 (4H, m), 6.92-7.00 (1H, m), 7.05 (1H, td), 7.13 (1H, d), 7.29-7.36 (1H, m), 7.52 (1H, d), 10.78 (1H, br s), m/z: ES+ [M+H]+ 247.

Preparation of (R)—N-(1-(1H-indol-3-yl)propan-2-yl)-1-fluorocyclopropane-1-carboxamide

Triethylamine (6.40 mL, 46.0 mmol) was added dropwise to a mixture of (R)-1-(1H-indol-3-yl)propan-2-amine (4.00 g, 23.0 mmol), 1-fluorocyclopropane-1-carboxylic acid (2.39 g, 23.0 mmol) and HATU (10.5 g, 27.6 mmol) in DCM (30 mL), and stirring was continued for 2 hours. Water was added, and the mixture was extracted with DCM. The extract was dried over Na₂SO₄, filtered, and concentrated under reduced pressure. The resulting residue was purified by flash silica chromatography, elution gradient 0 to 90% EtOAc in hexane, to afford (R)—N-(1-(1H-indol-3-yl)propan-2-yl)-1-fluorocyclopropane-1-carboxamide (5.2 g, 87%) as a white solid. ¹H NMR (300 MHz, DMSO-d₆) 1.12 (3H, d), 1.14-1.32 (4H, m), 2.77 (1H, dd), 2.90-3.01 (1H, m), 4.09-4.26 (1H, m), 6.93-7.01 (1H, m), 7.06 (1H, td), 7.12 (1H, d), 7.28-7.39 (1H, m), 7.58 (1H, d), 8.15 (1H, br d), 10.78 (1H, br s). m/z: ES+ [M+H]+ 261.

Preparation of tert-butyl 3-fluoropropyl(2-hydroxyethyl)carbamate

A solution of 1-iodo-3-fluoropropane (7.0 g, 37 mmol) in acetonitrile (10 mL) was added to a suspension of ethanolamine (4.50 mL, 74.5 mmol) and potassium carbonate (25.7 g, 186 mmol) in acetonitrile (60 mL). The mixture was stirred at room temperature for 5 hours and then diluted with DCM (20 ml). The mixture was cooled to 0° C. and di-tert-butyl dicarbonate (19.0 mL, 81.9 mmol) was added. The mixture was stirred at room temperature for 3 hours and filtered. The filtrate was concentrated under reduced pressure, and the resulting residue was purified by flash silica chromatography, elution gradient 0 to 4% methanol in DCM, to afford tert-butyl (3-fluoropropyl)(2-hydroxyethyl)carbamate (3.82 g, 46%) as a colorless oil. ¹H NMR (300 MHz, DMSO-d₆) 1.4 (9H, s), 1.70-2.00 (2H, m), 3.10-3.20 (2H, m), 3.30 (2H, d), 3.50 (2H, d), 4.30-4.60 (2H, m), 4.60 (1H, br t). m/z: ES+ [M+Na]+ 244.

Example 7 Preparation of 3-fluoro-N-(2-((5-((1R,3R)-2-((3-fluorooxetan-3-yl)methyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)-4-methoxypyridin-2-yl)oxy)ethyl)propan-1-amine

10% Palladium on activated charcoal (36.2 mg, 0.03 mmol) was added to a solution of benzyl (2-((5-((1R,3R)-2-((3-fluorooxetan-3-yl)methyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)-4-methoxypyridin-2-yl)oxy)ethyl)(3-fluoropropyl)carbamate (216 mg, 0.34 mmol) in EtOH (20 mL) under a stream of nitrogen. The mixture was evacuated and backfilled with hydrogen (2×) before stirring at room temperature under an atmosphere of hydrogen for 16 hours. The reaction was filtered through Celite® washing with MeOH (60 mL). The filtrate was concentrated in vacuo and the crude product was purified by preparative LCMS (Waters XSelect CSH C18 column, 5μ silica, 50 mm diameter, 100 mm length), using decreasingly polar mixtures of water (containing 1% NH₃) and MeCN as eluents. Fractions containing the desired compound were combined and concentrated (Genevac) to afford 3-fluoro-N-(2-((5-((1R,3R)-2-((3-fluorooxetan-3-yl)methyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)-4-methoxypyridin-2-yl)oxy)ethyl)propan-1-amine (56.0 mg, 33%) as a white crystalline solid. ¹H NMR (500 MHz, CDCl₃) 1.19 (3H, d), 1.83-1.89 (1H, m), 1.89-1.94 (1H, m), 2.49-2.64 (1H, m), 2.80 (3H, t), 2.96 (3H, dd), 3.16 (1H, dd), 3.33-3.47 (1H, m), 3.90 (3H, s), 4.34 (2H, ddd), 4.42-4.52 (2H, m), 4.57 (1H, d), 4.64-4.81 (3H, m), 5.31 (1H, s), 6.26 (1H, s), 7.07-7.12 (1H, m), 7.12-7.16 (1H, m), 7.22-7.25 (1H, m), 7.42 (1H, s), 7.49-7.53 (1H, m), 7.73 (1H, s). m/z: ES+ [M+H]+ 501.

The benzyl (2-((5-((1R,3R)-2-((3-fluorooxetan-3-yl)methyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)-4-methoxypyridin-2-yl)oxy)ethyl)(3-fluoropropyl)carbamate used as starting material was prepared as follows;

Preparation of (1R,3R)-1-(6-chloro-4-methoxypyridin-3-yl)-2-((3-fluorooxetan-3-yl)methyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole

Acetic acid (0.750 mL) was added to a solution of (R)—N-((3-fluorooxetan-3-yl)methyl)-1-(1H-indol-3-yl)propan-2-amine (115 mg, 0.44 mmol) and 6-chloro-4-methoxynicotinaldehyde (79 mg, 0.46 mmol) in toluene (3 mL). The reaction was warmed to 80° C. under nitrogen for 5 hours and then allowed to cool to room temperature. The reaction mixture was basified with saturated aqueous sodium bicarbonate then extracted with EtOAc (2×40 mL). The combined organic phases were washed with saturated aqueous sodium chloride and then dried over magnesium sulfate, filtered and concentrated in vacuo. The crude product was purified by flash silica chromatography, elution gradient 0 to 100% EtOAc in heptane. Product containing fractions were evaporated to dryness to afford (1R,3R)-1-(6-chloro-4-methoxypyridin-3-yl)-2-((3-fluorooxetan-3-yl)methyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole (140 mg, 77%) as a white solid. ¹H NMR (500 MHz, CDCl₃) 1.20 (3H, d), 2.60 (1H, ddd), 2.77 (1H, dd), 2.86-2.99 (1H, m), 3.18 (1H, dd), 3.29-3.40 (1H, m), 3.97 (3H, s), 4.43 (1H, dd), 4.62-4.84 (3H, m), 5.37 (1H, d), 6.86 (1H, s), 7.12 (1H, ddd), 7.15-7.20 (1H, m), 7.25-7.28 (1H, m), 7.51-7.55 (1H, m), 7.65 (1H, s), 7.72 (1H, s). m/z: ES+ [M+H]+ 416.

Preparation of 6-chloro-4-methoxynicotinaldehyde

Sodium methoxide (0.068 g, 1.25 mmol) was added portionwise to a stirred solution of 4,6-dichloronicotinaldehyde (0.2 g, 1.14 mmol) in MeOH (10 mL) cooled to 0° C. The reaction was allowed to warm to room temperature (over 5 hours) and stirred at room temperature for 16 hours. The reaction was concentrated in vacuo and then dissolved in DCM. Solids were removed by filtration and the filtrate was purified by flash silica chromatography, elution gradient 0 to 50% EtOAc in heptane. Pure fractions were evaporated to dryness to afford 6-chloro-4-methoxynicotinaldehyde (0.111 g, 57%) as a white solid. ¹H NMR (500 MHz, CDCl₃, 22° C.) 4.02 (3H, s), 6.97 (1H, s), 8.69 (1H, s), 10.37 (1H, d). m/z: ES+ [M+H]+ 172.

Preparation of 4,6-dichloronicotinaldehyde

A stirred −60° C. solution of ethyl 4,6-dichloronicotinate (4.0 g, 18.2 mmol) in DCM (70 mL) was treated dropwise with diisobutylaluminum hydride (1M in toluene) (20.0 mL, 20.0 mmol) over 20 mins (temperature −50° C. to −60° C. during addition), and stirred at −60° C. for 3 hours. The reaction was quenched by dropwise addition of 1M HCl (50 mL) and stirred for 1 hour. Extra DCM (100 mL) was added, the layers separated, and the aqueous layer was extracted with another portion of DCM (100 mL). The combined organic layers were washed with brine, dried and evaporated to give a crude solid which was purified by flash silica chromatography, elution gradient 0 to 20% EtOAc in heptane. Pure fractions were evaporated to dryness to afford 4,6-dichloronicotinaldehyde (2.55 g, 80%) as a white crystalline solid. ¹H NMR (500 MHz, DMSO-d₆, 27° C.) 8.02 (1H, d), 8.80 (1H, t), 10.25 (1H, s). m/z: ES+ [M+MeOH₂]+ 208.

Preparation of benzyl (3-fluoropropyl)(2-hydroxyethyl)carbamate

A solution of 1-fluoro-3-iodopropane (7.79 g, 41.4 mmol) in acetonitrile (50 mL) was added slowly to a suspension of potassium carbonate (28.6 g, 207 mmol) and 2-aminoethane-1-ol (2.50 mL, 41.4 mmol) in acetonitrile (200 mL) and the reaction mixture was stirred at room temperature for 16 hours. Benzyl chloroformate (8.87 mL, 62.1 mmol) was added dropwise over 5 minutes and the reaction was stirred at room temperature for a further 16 hours. The reaction was diluted with EtOAc (400 mL) and then washed with water (100 mL), 2M HCl (2×100 mL) and saturated aqueous sodium chloride (100 mL). The organic phase was separated and dried over magnesium sulfate, filtered and concentrated in vacuo to a yellow oil. The crude product was purified by flash chromatography, elution gradient 0 to 60% EtOAc in heptane. Pure fractions were evaporated to dryness to afford benzyl (3-fluoropropyl)(2-hydroxyethyl)carbamate (6.56 g, 62%) as a yellow oil. ¹H NMR (500 MHz, DMSO-d₆) 1.87 (2H, ddd), 3.27 (2H, s), 3.36 (2H, d), 3.48 (2H, q), 4.43 (2H, dd), 4.70 (1H, d), 5.06 (2H, s), 7.26-7.41 (5H, m).

Preparation of benzyl (2-((5-((1R,3R)-2-((3-fluorooxetan-3-yl)methyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)-4-methoxypyridin-2-yl)oxy)ethyl)(3-fluoropropyl)carbamate

(1R,3R)-1-(6-Chloro-4-methoxypyridin-3-yl)-2-((3-fluorooxetan-3-yl)methyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole (140 mg, 0.34 mmol), cesium carbonate (274 mg, 0.84 mmol) and RockPhos 3^(rd) Generation Precatalyst (28.5 mg, 0.03 mmol) were charged to a flask and the flask evacuated and back filled with nitrogen. A solution of benzyl (3-fluoropropyl)(2-hydroxyethyl)carbamate (1.346 mL, 0.67 mmol) in degassed toluene (2 mL) was added. The vessel was evacuated and back filled with nitrogen 2 times and then the reaction was stirred vigorously at 90° C. overnight. After cooling, the reaction was partitioned between water (20 mL) and ethyl acetate (80 mL). The layers were separated and the organic phase was washed with saturated aqueous sodium chloride (20 mL), dried over magnesium sulfate, filtered and concentrated in vacuo to afford crude benzyl (2-((5-((1R,3R)-2-((3-fluorooxetan-3-yl)methyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)-4-methoxypyridin-2-yl)oxy)ethyl)(3-fluoropropyl)carbamate as a gum which was used without further purification

Example 8 Preparation of 3-fluoro-N-(2-(4-((1R,3R)-2-((3-fluorooxetan-3-yl)methyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)-3-methoxyphenoxy)ethyl)propan-1-amine

10% Palladium on activated charcoal (40.4 mg, 0.04 mmol) was added to a solution of benzyl (2-(4-((1R,3R)-2-((3-fluorooxetan-3-yl)methyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)-3-methoxyphenoxy)ethyl)(3-fluoropropyl)carbamate (241 mg, 0.38 mmol) in EtOH (20 mL) under a stream of nitrogen. The mixture was evacuated and backfilled with hydrogen (2×) before stirring at room temperature under an atmosphere of hydrogen for 16 hours. The reaction was filtered through Celite® washing with MeOH (60 mL). The filtrate was concentrated in vacuo and the crude product was purified by preparative LCMS (Waters XSelect CSH C18 column, 5μ silica, 50 mm diameter, 100 mm length), using decreasingly polar mixtures of water (containing 1% NH₃) and MeCN as eluents. Fractions containing the desired product were combined and concentrated (Genevac) to afford 3-fluoro-N-(2-(4-((1R,3R)-2-((3-fluorooxetan-3-yl)methyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)-3-methoxyphenoxy)ethyl)propan-1-amine (41.0 mg, 22%) as a beige gum. ¹H NMR (500 MHz, CDCl₃) 1.16 (3H, d), 1.90 (2H, dddd), 2.60 (1H, ddd), 2.81 (2H, t), 2.84-2.96 (2H, m), 2.96-3.01 (2H, m), 3.12 (1H, dd), 3.42-3.52 (1H, m), 3.90 (3H, s), 3.99-4.07 (2H, m), 4.44 (1H, dd), 4.49 (1H, t), 4.54-4.63 (2H, m), 4.64-4.76 (2H, m), 5.33 (1H, s), 6.33 (1H, dd), 6.53 (1H, d), 6.83 (1H, d), 7.07-7.15 (2H, m), 7.20-7.24 (1H, m), 7.49-7.54 (1H, m), 7.67 (1H, s). m/z: ES+ [M+H]+ 500.

The benzyl (2-(4-((1R,3R)-2-((3-fluorooxetan-3-yl)methyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)-3-methoxyphenoxy)ethyl)(3-fluoropropyl)carbamate used as starting material was prepared as follows;

Preparation of (1R,3R)-1-(4-bromo-2-methoxyphenyl)-2-((3-fluorooxetan-3-yl)methyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole

Acetic acid (0.750 mL) was added to a solution of (R)—N-((3-fluorooxetan-3-yl)methyl)-1-(1H-indol-3-yl)propan-2-amine (115 mg, 0.44 mmol) and 4-bromo-2-methoxybenzaldehyde (99 mg, 0.46 mmol) in toluene (3 mL). The reaction was warmed to 80° C. under nitrogen for 5 hours and then allowed to cool to room temperature. The reaction mixture was basified with saturated aqueous sodium bicarbonate then extracted with EtOAc (2×40 mL). The combined organic phases were washed with saturated aqueous sodium chloride and then dried over magnesium sulfate, filtered and concentrated in vacuo. The crude product was purified by flash silica chromatography, elution gradient 0 to 30% EtOAc in heptane. Product containing fractions were evaporated to dryness to afford (1R,3R)-1-(4-bromo-2-methoxyphenyl)-2-((3-fluorooxetan-3-yl)methyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole (176 mg, 87%) as a white solid. ¹H NMR (500 MHz, CDCl₃) 1.17 (3H, d), 2.61 (1H, ddd), 2.79-2.89 (1H, m), 2.88-2.98 (1H, m), 3.15 (1H, dd), 3.36-3.45 (1H, m), 3.93 (3H, s), 4.43 (1H, dd), 4.61 (1H, dd), 4.71 (2H, td), 5.36 (1H, s), 6.80 (1H, d), 6.94 (1H, dd), 7.08 (1H, d), 7.09-7.12 (1H, m), 7.12-7.16 (1H, m), 7.22-7.26 (1H, m), 7.49-7.54 (1H, m), 7.63 (1H, s). m/z: ES+ [M−H]− 457 and 459.

Preparation of benzyl (2-(4-((1R,3R)-2-((3-fluorooxetan-3-0)methyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)-3-methoxyphenoxy)ethyl)(3-fluoropropyl)carbamate

(1R,3R)-1-(4-bromo-2-methoxyphenyl)-2-((3-fluorooxetan-3-yl)methyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole (176 mg, 0.38 mmol), cesium carbonate (312 mg, 0.96 mmol) and RockPhos 3^(rd) Generation Precatalyst (32.5 mg, 0.04 mmol) were charged to a flask and the flask evacuated and back filled with nitrogen. A 0.5M toluene solution of benzyl (3-fluoropropyl)(2-hydroxyethyl)carbamate (1.533 mL, 0.77 mmol) was added. The vessel was evacuated and back filled with nitrogen (×2) and then the reaction was stirred vigorously at 90° C. overnight. After cooling to room temperature, the reaction was partitioned between water (20 mL) and ethyl acetate (20 mL). The layers were separated and the aqueous was extracted with ethyl acetate (2×20 mL). The combined organic layers were washed with saturated aqueous sodium chloride (20 mL), dried over magnesium sulfate, filtered and concentrated in vacuo to give crude benzyl (2-(4-((1R,3R)-2-((3-fluorooxetan-3-yl)methyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)-3-methoxyphenoxy)ethyl)(3-fluoropropyl)carbamate that was used without further purification.

Example 9 Preparation of N¹-(3,5-difluoro-4-((1R,3R)-2-((1-fluorocyclopropyl)methyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)phenyl)-N²-(3-fluoropropyl)ethane-1,2-diamine

Palladium on carbon (10 wt %; 19 mg, 0.18 mmol) was added to a degassed solution of benzyl (2-((3,5-difluoro-4-((1R,3R)-2-((1-fluorocyclopropyl)methyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)phenyl)amino)ethyl)(3-fluoropropyl)carbamate (110 mg, 0.18 mmol) in ethanol (1 mL). The mixture was stirred under a hydrogen atmosphere (balloon) for 35 minutes. Nitrogen gas was bubbled through the reaction for 5 min to remove excess hydrogen, the catalyst was removed by filtration, and the filtrate was concentrated under reduced pressure. The resulting residue was purified by flash silica chromatography, elution gradient 0 to 20% methanol in DCM, to afford N¹-(3,5-difluoro-4-((1R,3R)-2-((1-fluorocyclopropyl)methyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)phenyl)-N²-(3-fluoropropyl)ethane-1,2-diamine (56.0 mg, 65%) as a light yellow foam solid. ¹H NMR (300 MHz, DMSO-d₆, 27° C.) 0.43-0.59 (2H, m), 0.78-0.97 (2H, m), 1.05 (3H, d), 1.69-1.92 (2H, m), 2.52-2.76 (6H, m), 2.87 (1H, br. dd), 2.96-3.19 (3H, m), 3.48-3.71 (1H, m), 4.50 (2H, dt), 5.06 (1H, s), 6.08-6.31 (3H, m), 6.84-7.05 (2H, m) 7.18 (1H, dd), 7.37 (1H, d), 10.45 (1H, s). Dialkyl NH not observed. m/z: ES+ [M+H]+ 489.

The starting material benzyl (2-((3,5-difluoro-4-((1R,3R)-2-((1-fluorocyclopropyl)methyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)phenyl)amino)ethyl)(3-fluoropropyl)carbamate was prepared as follows;

Preparation of benzyl (2-((tert-butoxycarbonyl)amino)ethyl)(3-fluoropropyl)carbamate

A solution of 1-iodo-3-fluoropropane (3.52 g, 18.7 mmol) in acetonitrile (5 mL) was added to a suspension of tert-butyl (2-aminoethyl)carbamate (5.0 g, 31 mmol) and potassium carbonate (8.63 g, 62.4 mmol) in acetonitrile (30 mL). The mixture was stirred at room temperature for 3 hours and then filtered. The filtrate was concentrated under reduced pressure and then DCM (50 mL) was added. The solution was cooled to 0° C., and DIPEA (7.10 mL, 40.7 mmol) was added followed by slow dropwise addition of benzyl chloroformate (4.56 mL, 32.0 mmol). Once addition was complete, the ice bath was removed, and the reaction mixture was stirred at room temperature for 6 hours. The reaction was diluted with water and extracted with ethyl acetate. The organic layer was dried over sodium sulfate, filtered, and concentrated under reduced pressure. The resulting residue was purified by flash silica chromatography, elution gradient 0 to 80% ethyl acetate in hexane, to give benzyl (2-((tert-butoxycarbonyl)amino)ethyl)(3-fluoropropyl)carbamate (2.1 g, 21%) as an oil. ¹H NMR (300 MHz, DMSO-d₆, 27° C.) 1.37 (9H, s), 1.74-1.98 (2H, m), 3.01-3.13 (2H, m), 3.19-3.41 (4H, m), 4.29-4.63 (2H, m), 5.07 (2H, s), 6.88 (1H, br. s), 7.30-7.39 (5H, m).

Preparation of benzyl (2-aminoethyl)(3-fluoropropyl)carbamate

Trifluoroacetic acid (3.48 mL, 45.1 mmol) was added to a solution of benzyl (2-((tert-butoxycarbonyl)amino)ethyl)(3-fluoropropyl)carbamate (1.6 g, 4.5 mmol) in DCM (16 mL) and stirred at room temperature for 1 hour. The reaction was then concentrated under reduced pressure, diluted with ethyl acetate, and washed with saturated aqueous sodium bicarbonate. The organic layer was dried over sodium sulfate, filtered and, concentrated under reduced pressure to give benzyl (2-aminoethyl)(3-fluoropropyl)carbamate (1.1 g, 98%) as a light yellow solid. ¹H NMR (300 MHz, DMSO-d₆, 27° C.) 1.73-1.98 (2H, m), 2.88 (2H, br. s), 3.37 (4H, q), 4.45 (2H, dt), 5.09 (2H, s), 6.43 (2H, br. s), 7.25-7.49 (5H, m).

Preparation of benzyl (2-((3,5-difluoro-4-((1R,3R)-2-((1-fluorocyclopropyl)methyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)phenyl)amino)ethyl)(3-fluoropropyl)carbamate

BrettPhos 3^(rd) Generation Precatalyst (20 mg, 0.020 mmol) was added to a degassed mixture of (1R,3R)-1-(4-bromo-2,6-difluorophenyl)-2-((1-fluorocyclopropyl)methyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole (200 mg, 0.45 mmol), benzyl (2-aminoethyl)(3-fluoropropyl)carbamate (147 mg, 0.58 mmol), and potassium carbonate (123 mg, 0.89 mmol) in THF (4 mL). The reaction vessel was sealed and warmed to 70° C. After 6 hours, additional BrettPhos 3^(rd) Generation Precatalyst (20 mg, 0.02 mmol) was added, and the reaction was maintained at 70° C. for an additional 36 hours. The reaction was concentrated under reduced pressure, and the resulting residue was purified by flash silica chromatography, elution gradient 0 to 80% ethyl acetate in hexanes, to give benzyl (2-((3,5-difluoro-4-((1R,3R)-2-((1-fluorocyclopropyl)methyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1 yl)phenyl)amino)ethyl)(3-fluoropropyl)carbamate (173 mg, 62%) as a light yellow foam solid. ¹H NMR (300 MHz, DMSO-d₆, 27° C.) 0.32-0.68 (2H, m), 0.76-0.96 (2H, m), 1.05 (3H, d), 1.67-1.95 (2H, m), 2.53-2.77 (2H, m), 2.86 (1H, dd), 3.08 (1H, dd), 3.21 (2H, br. s), 3.31-3.42 (4H, m), 3.46-3.75 (1H, m), 4.42 (2H, dt), 4.99-5.17 (3H, m), 6.05-6.41 (3H, m), 6.82-7.07 (2H, m), 7.13-7.25 (1H, m), 7.26-7.50 (6H, m), 10.46 (1H, s).

Example 10 Preparation of 3-((1R,3R)-1-(2,6-difluoro-4-(2-((3-fluoropropyl)amino)ethoxy)phenyl)-3-methyl-1,3,4,9-tetrahydro-2H-pyrido[3,4-b]indol-2-yl)-2,2-difluoropropan-1-ol

TFA (0.309 mL, 4.01 mmol) in DCM (1 mL) was added to a stirred solution of tert-butyl (2-(4-((1R,3R)-2-(2,2-difluoro-3-hydroxypropyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)-3,5-difluorophenoxy)ethyl)(3-fluoropropyl)carbamate (98 mg, 0.16 mmol) in DCM (2 mL) at 0° C. The mixture was stirred at room temperature for 40 minutes and then quenched with saturated aqueous NaHCO₃. The mixture was extracted with DCM, and the organic layer was dried over sodium sulfate, filtered, and concentrated under reduced pressure. The resulting residue was purified by preparative HPLC (Waters Xbridge C18 column, 19 mm diameter, 150 mm length, 5 μm; 20 mL/min) using decreasingly polar mixtures of water (containing 0.2% ammonium hydroxide) and MeCN as eluents (60 to 95% over 5 min) to afford 3-((1R,3R)-1-(2,6-difluoro-4-(2-((3-fluoropropyl)amino)ethoxy)phenyl)-3-methyl-1,3,4,9-tetrahydro-2H-pyrido[3,4-b]indol-2-yl)-2,2-difluoropropan-1-ol (21 mg, 26%) as white solid. ¹H NMR (400 MHz, DMSO-d₆, 27° C.) 1.07 (3H, br. d), 1.69-1.85 (3H, m), 2.53-2.67 (4H, m), 2.74-2.86 (3H, m), 3.06-3.16 (1H, m), 3.37-3.50 (2H, m), 3.56-3.71 (1H, m), 4.01 (2H, br. t), 4.47 (2H, dt), 5.14 (1H, s), 5.26 (1H, br. s), 6.65 (2H, br. d), 6.88-7.04 (2H, m), 7.18 (1H, br. d), 7.39 (1H, br. d), 10.55 (1H, s). m/z: ES+ [M+H]+ 512.

The starting material tert-butyl (2-(4-((1R,3R)-2-(2,2-difluoro-3-hydroxypropyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)-3,5-difluorophenoxy)ethyl)(3-fluoropropyl)carbamate was prepared as follows;

Preparation 3-((tert-butyldiphenylsilyl)oxy)-2,2-difluoropropan-1-ol

NaH in mineral oil (60 wt %; 343 mg, 8.58 mmol) was added in one portion to a stirred solution of 2,2-difluoropropane-1,3-diol (874 mg, 7.80 mmol) in THF (32 mL) at 0° C. The reaction was allowed to warm to room temperature, and was stirred at room temperature for 2 h. The reaction mixture was again cooled to 0° C., and tert-butyldiphenylchlorosilane (2.0 mL, 7.8 mmol) was added dropwise via syringe. The reaction mixture was allowed to warm to room temperature over 1 hour and was then quenched with water and extracted with EtOAc. The organic layer was dried with Na₂SO₄, filtered, and the filtrate was concentrated under reduced pressure. The resulting residue was purified by flash silica chromatography, eluting with isocratic 5% ethyl acetate in hexanes, to afford 3-((tert-butyldiphenylsilyl)oxy)-2,2-difluoropropan-1-ol (1.94, 71%) as a colorless oil. ¹H NMR (300 MHz, CHLOROFORM-d, 27° C.) δ ppm 1.03-1.14 (9H, s), 3.87-3.93 (4H, m), 7.37-7.44 (6H, m), 7.64-7.66 (4H, m).

Preparation of 3-((tert-butyldiphenylsilyl)oxy)-2,2-difluoropropyl trifluoromethanesulfonate

A solution of 3-((tert-butyldiphenylsilyl)oxy)-2,2-difluoropropan-1-ol (1.94 g, 5.55 mmol) and 2,6-dimethylpyridine (1.94 ml, 16.6 mmol) in DCM (18 ml) was cooled to −10° C. (salt/ice bath). Trifluoromethanesulfonic anhydride (1.88 ml, 11.1 mmol) was added slowly dropwise over 10 minutes. The reaction was maintained under these conditions for 2 hours. The reaction was then washed with water, aqueous HCl (1N; 100 mL), and saturated aqueous sodium bicarbonate. The organic layer was dried over MgSO₄, filtered, and concentrated under reduced pressure to afford 3-((tert-butyldiphenylsilyl)oxy)-2,2-difluoropropyl trifluoromethanesulfonate (2.68 g, 100%) as a red oil. ¹H NMR (300 MHz, CHLOROFORM-d, 27° C.) 1.03-1.14 (9H, s), 3.90 (2H, t), 4.76 (2H, t), 7.39-7.56 (6H, m), 7.59-7.75 (4H, m).

Preparation of (R)—N-(1-(1H-indol-3-yl)propan-2-yl)-3-((tert-butyldiphenylsilyl)oxy)-2,2-difluoropropan-1-amine

3-((Tert-butyldiphenylsilyl)oxy)-2,2-difluoropropyl trifluoromethanesulfonate (481 mg, 1.00 mmol) was added to a stirred solution of (R)-1-(1H-indol-3-yl)propan-2-amine (174 mg, 1.00 mmol) in 1,4-dioxane (3 mL), followed by DIPEA (0.244 mL, 1.40 mmol). The reaction was stirred at 85° C. for 5 hours. The reaction was poured into a mixture of DCM and saturated aqueous sodium bicarbonate. The organic layer was dried over sodium sulfate, filtered, and concentrated. The resulting residue was purified by flash silica chromatography, elution gradient 0 to 35% ethyl acetate in hexanes, to yield (R)—N-(1-(1H-indol-3-yl)propan-2-yl)-3-((tert-butyldiphenylsilyl)oxy)-2,2-difluoropropan-1-amine (465 mg, 92%). m/z: ES+ [M+H]+ 507.

Preparation of (1R,3R)-1-(4-bromo-2,6-difluorophenyl)-2-(3-((tert-butyldiphenylsilyl)oxy)-2,2-difluoropropyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole

A mixture of (R)—N-(1-(1H-indol-3-yl)propan-2-yl)-3-((tert-butyldiphenylsilyl)oxy)-2,2-difluoropropan-1-amine (463 mg, 0.91 mmol), 4-bromo-2,6-difluorobenzaldehyde (212 mg, 0.96 mmol), toluene (3 mL) and acetic acid (0.105 mL, 1.83 mmol) was heated at 106° C. for 5 hours. The reaction was poured into DCM and saturated aqueous sodium hydrogencarbonate. The layers were separated, and the organic layer was dried over sodium sulfate, filtered, and concentrated under reduced pressure. The resulting residue was purified by flash silica chromatography, elution gradient 0 to 30% ethyl acetate in hexanes, to yield (1R,3R)-1-(4-bromo-2,6-difluorophenyl)-2-(3-((tert-butyldiphenylsilyl)oxy)-2,2-difluoropropyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole (560 mg, 86%) as light yellow solid. ¹H NMR (300 MHz, CDCl₃, 27° C.) 1.07 (9H, s), 1.16 (3H, d), 2.61 (1H, ddd), 2.70-2.87 (1H, m), 3.00 (1H, ddd), 3.29 (1H, ddd), 3.57-3.71 (2H, m), 3.96 (1H, dt), 5.29 (1H, s), 6.91-7.02 (2H, m), 7.10-7.15 (2H, m), 7.20-7.24 (1H, m), 7.37-7.46 (7H, m), 7.61-7.68 (4H, m). m/z: ES+ [M+H]+ 709.

Preparation of tert-butyl (2-(4-((1R,3R)-2-(3-((tert-butyldiphenylsilyl)oxy)-2,2-difluoropropyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)-3,5-difluorophenoxy)ethyl)(3-fluoropropyl)carbamate

A vial was charged with (1R,3R)-1-(4-bromo-2,6-difluorophenyl)-2-(3-((tert-butyldiphenylsilyl)oxy)-2,2-difluoropropyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole (290 mg, 0.41 mmol), tert-butyl (3-fluoropropyl)(2-hydroxyethyl)carbamate (136 mg, 0.61 mmol), cesium carbonate (333 mg, 1.02 mmol) and RockPhos 3^(rd) Generation Precatalyst (35 mg, 0.04 mmol). The vial was degassed and refilled with nitrogen. Toluene (3 mL) was added, and the vial was degassed and refilled with nitrogen (2×). The mixture was heated at 90° C. for 18 hours. The reaction was diluted with water and extracted with DCM. The organic layer was dried over sodium sulfate, filtered, and concentrated under reduced pressure. The resulting residue was purified by flash silica chromatography, elution gradient 0 to 50% ethyl acetate in hexanes, to yield tert-butyl (2-(4-((1R,3R)-2-(3-((tert-butyldiphenylsilyl)oxy)-2,2-difluoropropyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)-3,5-difluorophenoxy)ethyl)(3-fluoropropyl)carbamate (320 mg, 92%). m/z: ES+ [M+H]+ 850.

Preparation of tert-butyl (2-(4-((1R,3R)-2-(2,2-difluoro-3-hydroxypropyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)-3,5-difluorophenoxy)ethyl)(3-fluoropropyl)carbamate

Tetrabutylammonium fluoride in THF (1 M; 0.57 mL, 0.56 mmol) was added to a solution of tert-butyl (2-(4-((1R,3R)-2-(3-((tert-butyldiphenylsilyl)oxy)-2,2-difluoropropyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)-3,5-difluorophenoxy)ethyl)(3-fluoropropyl)carbamate (320 mg, 0.38 mmol) in THF (2 mL). The reaction was stirred at 60° C. for 1 hour and then cooled to room temperature. After 18 hours, the reaction was diluted with DCM and washed with saturated aqueous ammonium chloride. The organic layer was dried over sodium sulfate, filtered, and concentrated under reduced pressure. The resulting residue was purified by flash silica chromatography, elution gradient 0 to 50% EtOAc in Hexanes, to yield tert-butyl (2-(4-((1R,3R)-2-(2,2-difluoro-3-hydroxypropyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)-3,5-difluorophenoxy)ethyl)(3-fluoropropyl)carbamate (223 mg, 97%). m/z: ES+ [M+H]+ 612.

Example 11 Preparation of 3-fluoro-N-(2-(4-((1R,3R)-2-((1-fluorocyclopropyl)methyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)-3-methoxyphenoxy)ethyl)propan-1-amine

Tert-butyl (2-(4-((1R,3R)-2-((1-fluorocyclopropyl)methyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)-3-methoxyphenoxy)ethyl)(3-fluoropropyl)carbamate (249 mg, 0.43 mmol) was dissolved in DCM (3 mL) and treated with TFA (0.329 mL, 4.27 mmol) dropwise. The purple reaction mixture was stirred at room temperature for 1.5 hours. The reaction was concentrated under reduced pressure, and the resulting residue was dissolved in EtOAc, washed with saturated aqueous NaHCO₃, dried over sodium sulfate, filtered, and concentrated under reduced pressure. The resulting residue was purified by preparative HPLC (Waters Xbridge C18 column, 5 μm silica, 19 mm diameter, 150 mm length, 20 mL/min), eluting with 60 to 95% acetonitrile in water containing 0.2% NH₄OH (pH 10) over 5 min. Product fractions were combined and concentrated under reduced pressure to afford 3-fluoro-N-(2-(4-((1R,3R)-2-((1-fluorocyclopropyl)methyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)-3-methoxyphenoxy)ethyl)propan-1-amine (149 mg, 72%) as an off-white foam. ¹H NMR (300 MHz, DMSO-d₆, 27° C.) δ ppm 0.56-0.69 (2H, m), 0.88-1.00 (2H, m), 1.04 (3H, d), 1.69-1.87 (3H, m), 2.53-2.69 (4H, m), 2.73-2.88 (3H, m), 3.07 (1H, dd), 3.48 (1H, d), 3.87 (3H, s), 3.98 (2H, t), 4.52 (2H, dt), 5.31 (1H, s), 6.37 (1H, dd), 6.60-6.65 (2H, m), 6.91-7.02 (2H, m), 7.18 (1H, d), 7.40 (1H, d), 10.29 (1H, s). m/z: ES+ [M+H]+ 484.

The starting material tert-butyl (2-(4-((1R,3R)-2-((1-fluorocyclopropyl)methyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)-3-methoxyphenoxy)ethyl)(3-fluoropropyl)carbamate was prepared as follows;

Preparation of (1R,3R)-1-(4-bromo-2-methoxyphenyl)-2-((1-fluorocyclopropyl)methyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole

(R)—N-((1-Fluorocyclopropyl)methyl)-1-(1H-indol-3-yl)propan-2-amine (340 mg, 1.38 mmol) and 4-bromo-2-methoxybenzaldehyde (277 mg, 1.29 mmol) were dissolved in toluene (6.0 mL) and treated with AcOH (0.67 mL). The reaction was heated at 80° C. for 18 hours. The reaction was diluted with EtOAc and quenched with saturated aqueous NaHCO₃. The layers were separated, and the organic layer was dried over sodium sulfate, filtered, and concentrated under reduced pressure. The resulting residue was purified by flash silica chromatography, elution gradient 0 to 40% EtOAc in hexanes. Pure fractions concentrated under reduced pressure to afford (1R,3R)-1-(4-bromo-2-methoxyphenyl)-2-((1-fluorocyclopropyl)methyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole (436 mg, 76%) as a light yellow foam. ¹H NMR (300 MHz, DMSO-d₆, 27° C.) 0.62 (2H, dd) 0.88-1.02 (2H, m), 1.05 (3H, d), 2.53-2.68 (2H, m) 2.82 (1H, dd) 3.07 (1H, dd) 3.37-3.55 (1H, m) 3.92 (3H, s) 5.35 (1H, s) 6.71 (1H, d) 6.90-7.04 (3H, m) 7.19 (1H, dd) 7.25 (1H, d) 7.42 (1H, d) 10.33 (1H, s). m/z: ES+ [M+H]+ 443.

Preparation of tert-butyl (2-(4-((1R,3R)-2-((1-fluorocyclopropyl)methyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)-3-methoxyphenoxy)ethyl)(3-fluoropropyl)carbamate

(1R,3R)-1-(4-bromo-2-methoxyphenyl)-2-((1-fluorocyclopropyl)methyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole (0.268 g, 0.60 mmol), tert-butyl (3-fluoropropyl)(2-hydroxyethyl)carbamate (0.20 g, 0.91 mmol), and cesium carbonate (0.394 g, 1.21 mmol) were dissolved in toluene (3 mL) in a 25 mL oven-dried flask. The solution was degassed with nitrogen and treated with RockPhos 3rd Generation Precatalyst (10 mg, 0.01 mmol). The reaction was heated at 90° C. for 1 hours. After cooling, the mixture was diluted with water and extracted with EtOAc. The organic layer was dried over sodium sulfate, filtered, and concentrated under reduced pressure. The resulting residue was purified by flash silica chromatography, elution gradient 0 to 50% EtOAc in hexanes. Pure fractions were combined and evaporated to dryness to afford tert-butyl (2-(4-((1R,3R)-2-((1-fluorocyclopropyl)methyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)-3-methoxyphenoxy)ethyl)(3-fluoropropyl)carbamate (253 mg, 72%) as a yellow foam. ¹H NMR (300 MHz, DMSO-d₆, 27° C.) 0.62 (2H, d), 0.88-1.00 (2H, m), 1.04 (3H, d), 1.38 (9H, s), 1.80-1.97 (2H, m), 2.53-2.67 (2H, m), 2.76-2.86 (1H, m), 3.07 (1H, dd), 3.31-3.38 (2H, m), 3.41-3.54 (3H, m), 3.87 (3H, s), 4.00-4.10 (2H, m), 4.45 (2H, dt), 5.31 (1H, s), 6.38 (1H, dd), 6.59-6.67 (2H, m), 6.91-7.02 (2H, m), 7.16-7.21 (1H, m), 7.40 (1H, d), 10.29 (1H, s). m/z: ES+ [M+H]+ 584.

Examples 12-39 (Table F below) were similarly prepared using methods analogous to those described above. Representative intermediates used in the preparation of Examples 12-39 are further described as follows;

Intermediate Used in the Preparation of Example 30 Preparation of (1S,3R)-1-(5-bromopyridin-2-yl)-2-(2-fluoro-2-methylpropyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole

5-Bromopicolinaldehyde (191 mg, 1.03 mmol) was added to a solution of (R)—N-(1-(1H-indol-3-yl)propan-2-yl)-2-fluoro-2-methylpropan-1-amine (33 wt % in toluene; 753 mg, 1.0 mmol) in toluene (4.5 mL) and acetic acid (0.5 mL). The reaction was heated to 80° C. and maintained under these conditions for 4 hours. After cooling, the volatiles were evaporated, and the resulting residue was dissolved in EtOAc. The organic layer was washed with saturated aqueous NaHCO₃, dried over sodium sulfate, filtered, and concentrated under reduced pressure. The resulting residue was purified by flash silica chromatography, elution gradient 0 to 50% EtOAc in heptane. Product fractions were evaporated to dryness to afford (1S,3R)-1-(5-bromopyridin-2-yl)-2-(2-fluoro-2-methylpropyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole (401 mg, 96%) as a colourless solid. ¹H NMR (500 MHz, CDCl₃, 27° C.) 1.29-1.38 (6H, m), 1.45 (3H, d), 2.57-2.74 (3H, m), 2.80 (1H, dd), 3.28 (1H, d), 5.12 (1H, s), 7.07 (1H, ddd), 7.14 (1H, ddd), 7.36 (1H, d), 7.48 (1H, dd), 7.70 (1H, d), 7.80 (1H, dd), 8.59 (1H, dd), 8.62 (1H, s). m/z: ES+ [M+H]+ 416.

Intermediates Used in the Preparation of Example 35 Preparation of (5-bromo-3-methoxypyridin-2-yl)methanol

4-methylmorpholine (0.507 ml, 4.61 mmol) and isobutyl chloroformate (0.598 ml, 4.61 mmol) were added to a solution of 5-bromo-3-methoxypicolinic acid (1.07 g, 4.61 mmol) in DME (8.12 ml) at −10° C. and the reaction was allowed to warm to room temperature over 30 min. The solids were filtered and washed with DME (8 mL). The filtrate was then treated with sodium borohydride (0.349 g, 9.22 mmol) and the reaction was stirred at room temperature for 30 min. Methanol (5 mL) was carefully added and the reaction was stirred for a further 30 min. The volatiles were evaporated, then the residue was dissolved in DCM (50 mL) and washed with water and brine. The organic phase was dried and evaporated to afford (5-bromo-3-methoxypyridin-2-yl)methanol (1.020 g, 100%) as a colourless solid. ¹H NMR (500 MHz, CDCl₃, 27° C.) 2.27 (1H, t), 3.96 (3H, s), 4.62 (2H, d), 7.72 (1H, dt), 8.12 (1H, d); m/z: ES+ [M+H]+ 218.

Preparation of 5-bromo-3-methoxypicolinaldehyde

Dess-Martin reagent (2.139 g, 5.04 mmol) was added to a solution of (5-bromo-3-methoxypyridin-2-yl)methanol (1.00 g, 4.59 mmol) in DCM (19.80 mL) and the reaction was stirred at room temperature for 1 hour. A solution of 2N Na₂CO₃ containing sodium thiosulfate solution (20 mL) was added and the bi-phasic mixture was stirred for 10 minutes. The layers were separated, then the aqueous was extracted with DCM. The combined organics were washed with brine, dried and evaporated. The crude product was purified by flash silica chromatography, elution gradient 0 to 50% EtOAc in heptane. Pure fractions were evaporated to dryness to afford 5-bromo-3-methoxypicolinaldehyde (0.914 g, 92%) as a colourless solid. ¹H NMR (500 MHz, CDCl₃, 27° C.) 4.07 (3H, s), 8.18 (1H, d), 8.41 (1H, d), 10.29 (1H, s); m/z: ES+ [M+H]+ 216.

Intermediates Used in the Preparation of Example 36 Preparation of (6-chloro-4-methoxypyridin-3-yl)methanol

Diisobutylaluminum hydride (1 M in toluene; 7.60 mL, 7.60 mmol) was added dropwise to a cooled solution of methyl 6-chloro-4-methoxynicotinate (958 mg, 4.75 mmol) in THF (11.4 mL) at −60° C. The reaction was maintained under these conditions for 1 hour. An additional portion of diisobutylaluminum hydride (0.5 equiv, 2.5 mL) was then added and the reaction was stirred for a further 1 hour. The reaction was quenched by addition of water and EtOAc. The layers were separated and the aqueous layer was extracted with EtOAc. The combined organic layers were washed with saturated aqueous sodium chloride, dried over sodium sulfate, filtered and concentrated under reduced pressure. The resulting residue was purified by flash silica chromatography, elution gradient 0 to 100% EtOAc in heptane. Product fractions were evaporated to dryness to afford 6-chloro-4-methoxynicotinaldehyde as a colourless solid (776 mg, 94%). ¹H NMR (500 MHz, CDCl₃, 27° C.) 2.14 (1H, t), 3.92 (3H, s), 4.67 (2H, d), 6.83 (1H, s), 8.19 (1H, s). m/z: ES+ [M+H]+ 174.

Preparation of 6-chloro-4-methoxynicotinaldehyde

Dess-Martin periodinane (2.08 g, 4.91 mmol) was added to a solution of (6-chloro-4-methoxypyridin-3-yl)methanol (775 mg, 4.46 mmol) in DCM (19.8 mL) and the reaction was stirred at room temperature for 1 hour. A solution of aqueous Na₂CO₃ (2N; 20 mL) was added and the biphasic mixture was stirred at room temperature for 10 minutes. The layers were separated and the aqueous layer was extracted with DCM. The combined organic layers were washed with saturated aqueous sodium chloride, dried over sodium sulfate, filtered and concentrated under reduced pressure. The resulting residue was purified by flash silica chromatography, elution gradient 0 to 50% EtOAc in heptane. Product fractions were evaporated to dryness to afford 6-chloro-4-methoxynicotinaldehyde (665 mg, 87%) as a colourless solid. ¹H NMR (500 MHz, CDCl₃, 27° C.) 4.02 (3H, s), 6.97 (1H, s), 8.68 (1H, s), 10.37 (1H, d). m/z: ES+ [M+H]+ 172.

Preparation of (1R,3R)-1-(6-chloro-4-methoxypyridin-3-yl)-2-(2-fluoro-2-methylpropyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole

6-Chloro-4-methoxynicotinaldehyde (180 mg, 1.05 mmol) was added to a solution of (R)—N-(1-(1H-indol-3-yl)propan-2-yl)-2-fluoro-2-methylpropan-1-amine (33 wt % in toluene; 753 mg, 1.00 mmol) in toluene (4.5 mL) and acetic acid (0.5 mL). The reaction was heated to 80° C. and maintained under these conditions for 4 hours. After cooling, the volatiles were evaporated and the resulting residue was dissolved in DCM and washed with saturated aqueous NaHCO₃. The organic layer was dried over sodium sulfate, filtered and concentrated under reduced pressure. The resulting residue was purified by flash silica chromatography, elution gradient 0 to 40% EtOAc in heptane. Product fractions were evaporated to dryness to afford (1R,3R)-1-(6-chloro-4-methoxypyridin-3-yl)-2-(2-fluoro-2-methylpropyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole (395 mg, 98%) as a colourless solid. ¹H NMR (500 MHz, CDCl₃, 27° C.) 1.13 (3H, d), 1.29 (3H, d), 1.38 (3H, d), 2.57 (2H, ddd), 2.62-2.82 (2H, m), 3.44 (1H, s), 3.98 (3H, s), 5.33 (1H, s), 6.85 (1H, s), 7.09 (1H, ddd), 7.11-7.17 (1H, m), 7.21-7.25 (1H, m), 7.45-7.54 (1H, m), 7.85 (1H, s), 7.87 (1H, s). m/z: ES+ [M+H]+ 402.

Intermediates Used in the Preparation of Example 38 Preparation of 5-chloropyrazine-2-carbaldehyde

Diisobutylaluminum hydride (1.0 M in toluene; 6.4 mL, 6.40 mmol) was added dropwise to a cooled solution of methyl 5-chloropyrazine-2-carboxylate (690 mg, 4.00 mmol) in THF (13.6 mL) at −55° C. The reaction was stirred under these conditions for 1 hour and then quenched by addition of saturated aqueous NH₄Cl (25 mL) and EtOAc (25 mL). An emulsion formed and 2N aqueous HCl was added to clear the emulsion (˜5 mL). The layers were separated, and the aqueous layer was extracted with EtOAc. The organic layer was washed with saturated aqueous sodium chloride, dried over magnesium sulfate and concentrated under reduced pressure. The resulting residue was purified by flash silica chromatography, elution gradient 0 to 50% EtOAc in heptane. Product fractions were evaporated to dryness to afford 5-chloropyrazine-2-carbaldehyde (385 mg, 68%) as a beige solid. ¹H NMR (500 MHz, CDCl₃, 27° C.) 8.75 (1H, d), 8.96 (1H, d), 10.15 (1H, d).

Preparation of (1S,3R)-1-(5-chloropyrazin-2-yl)-2-(2-fluoro-2-methylpropyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole

5-Chloropyrazine-2-carbaldehyde (314 mg, 2.20 mmol) was added to a solution of (R)—N-(1-(1H-indol-3-yl)propan-2-yl)-2-fluoro-2-methylpropan-1-amine (33% wt in toluene; 1.7 g, 2.2 mmol) in toluene (7.9 mL) and acetic acid (0.9 mL). The reaction was heated to 90° C. After 4 hours, the reaction was cooled, the volatiles were evaporated, and the resulting residue was dissolved in EtOAc. This organic layer was washed with saturated aqueous NaHCO₃, dried over sodium sulfate, filtered, and concentrated under reduced pressure. The resulting residue was purified by flash silica chromatography, elution gradient 0 to 50% EtOAc in heptane. Product fractions were evaporated to dryness to afford (1S,3R)-1-(5-chloropyrazin-2-yl)-2-(2-fluoro-2-methylpropyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole (791 mg, 96%) as a beige solid. ¹H NMR (500 MHz, CDCl₃, 27° C.) 1.30 (3H, s), 1.33 (3H, d), 1.50 (3H, d), 2.63 (2H, d), 2.70-2.85 (2H, m), 3.23 (1H, q), 5.30 (1H, s), 7.09 (1H, ddd), 7.17 (1H, ddd), 7.38 (1H, dt), 7.49 (1H, d), 8.48 (1H, s), 8.49 (1H, d), 8.84-8.87 (1H, m). m/z: ES+ [M+H]+ 373.

Intermediates Used in the Preparation of Example 39 Preparation of 5-bromopyrimidine-2-carbaldehyde

Diisobutylaluminum hydride (1M in toluene; 3.46 mL, 3.46 mmol) was added dropwise to a cooled solution of ethyl 5-bromopyrimidine-2-carboxylate (0.500 g, 2.16 mmol) in THF (7.36 mL) at −55° C. The reaction was maintained under these conditions for 1 hour and then quenched by addition of saturated aqueous NH₄Cl (20 mL) and EtOAc (20 mL). An emulsion formed, and 2N HCl was added to clear the emulsion (˜4 mL). The layers were separated, and the aqueous layer was extracted with EtOAc. The combined organic layers were washed with saturated aqueous sodium chloride, dried over magnesium sulfate and concentrated under reduced pressure to afford 5-bromopyrimidine-2-carbaldehyde (0.589 g, >100%) which was used directly in the next step without further purification. ¹H NMR (500 MHz, CDCl₃, 27° C.) 9.05 (2H, s), 10.09 (1H, s).

Preparation of (1S,3R)-1-(5-bromopyrimidin-2-yl)-2-(2-fluoro-2-methylpropyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole (40)

5-Bromopyrimidine-2-carbaldehyde (262 mg, 1.40 mmol) was added to a solution of (R)—N-(1-(1H-indol-3-yl)propan-2-yl)-2-fluoro-2-methylpropan-1-amine (33% wt in toluene; 1.10 g, 1.40 mmol) in toluene (6.3 mL) and acetic acid (0.7 mL). The reaction was heated to 90° C. After 4 hours, the reaction was cooled, and volatiles were evaporated. The resulting residue was dissolved in EtOAc, and the resulting solution was washed with saturated aqueous NaHCO₃, dried over sodium sulfate, filtered, and concentrated under reduced pressure. The resulting residue was purified by flash silica chromatography, elution gradient 0 to 50% EtOAc in heptane. Product fractions were evaporated to dryness to afford (1S,3R)-1-(5-bromopyrimidin-2-yl)-2-(2-fluoro-2-methylpropyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole (455 mg, 78%) as a beige solid. ¹H NMR (500 MHz, CDCl₃, 27° C.) 1.27 (3H, d), 1.33 (3H, d), 1.46 (3H, d), 2.53-2.64 (1H, m), 2.64-2.75 (2H, m), 2.75-2.88 (1H, m), 3.72 (1H, ddd), 5.35-5.40 (1H, m), 7.07 (1H, ddd), 7.13 (1H, ddd), 7.25-7.34 (1H, m), 7.43-7.55 (1H, m), 8.25 (1H, s), 8.76 (2H, s). m/z: ES+ [M+H]+ 417.

TABLE F LCMS Example Structure Name 1H NMR [M + H] 12

N-(2-(4- ((1R,3R)-2- (2,2- difluoropropyl)- 3-methyl- 2,3,4,9- tetrahydro-1H- pyrido[3,4- b]indol-1-yl)- 3,5-difluoro- phenoxy) ethyl)-3- fluoropropan- 1-amine ¹H NMR (500 MHz, DMSO, 27° C.) 1.08 (3H, d), 1.45 (3H, t), 1.72-1.83 (3H, m), 2.55-2.67 (4H, m), 2.82-2.9 (3H, m), 3.01-3.11 (1H, m), 3.4- 3.48 (1H, m), 4.03 (2H, t), 4.49 (2H, dt), 5.15 (1H, s), 6.68 (2H, d), 6.94 (1H, ddd), 7.00 (1H, ddd), 7.19 (1H, dt), 7.40 (1H, d), 10.57 (1H, s). 496 13

N-(2-(4- ((1R,3R)-2- (2,2- difluoroethyl)- 3-methyl- 2,3,4,9- tetrahydro-1H- pyrido[3,4- b]indol-1-yl)- 3,5-difluoro- phenoxy) ethyl)-3- fluoropropan- 1-amine ¹H NMR (500 MHz, DMSO, 27° C.) 1.09 (3H, d), 1.73-1.82 (3H, m), 2.54-2.60 (1H, m), 2.62-2.68 (3H, m), 2.81-2.88 (3H, m), 3.01-3.13 (1H, m), 3.34-3.42 (1H, m), 4.03 (2H, t), 4.49 (2H, dt), 5.17 (1H, s), 5.87 (1H, tt), 6.68 (2H, d), 6.95 (1H, ddd), 7.00 (1H, ddd), 7.20 (1H, dt), 7.40 (1H, d), 10.59 (1H, s). 480 14

N-(2-(4- ((1R,3R)-2- (2,2-difluoro- 3-methoxy- propyl)- 3-methyl- 2,3,4,9- tetrahydro-1H- pyrido[3,4- b]indol-1-yl)- 3,5-difluoro- phenoxy) ethyl)-3- fluoropropan- 1-amine ¹H NMR (300 MHz, DMSO-d6) 1.08 (d, 3H) 1.61-1.90 (m, 3H) 2.53-2.72 (m, 4H) 2.77-2.98 (m, 3H) 2.99-3.21 (m, 1H) 3.24 (s, 3H) 3.34-3.73 (m, 3H) 4.03 (t, 2H) 4.42 (t, 1H) 4.58 (t, 1H) 5.15 (s, 1H) 6.62- 6.72 (m, 2H) 6.89- 7.06 (m, 2H) 7.20 (dd, 1H) 7.40 (d, 1H) 10.56 (s, 1H) 526 15

N-(2-(4- ((1R,3R)-2- (2,3-difluoro- propyl)- 3-methyl- 2,3,4,9- tetrahydro-1H- pyrido[3,4- b]indol-1-yl)- 3,5-difluoro- phenoxy) ethyl)-3- fluoropropan- 1-amine ¹H NMR (500 MHz, CDCl₃, 27° C.) 1.15 (3H, d), 1.85-1.97 (2H, m), 2.59-2.65 (1H, m), 2.68-2.77 (1H, m), 2.84 (2H, t), 2.98-3.09 (4H, m), 3.46-3.53 (1H, m), 4.04 (2H, t), 4.38-4.73 (5H, m), 5.18 (1H, s), 6.41-6.46 (2H, m), 7.08-7.15 (2H, m), 7.22-7.25 (1H, m), 7.48 (1H, s), 7.50-7.53 (1H, m). 496 16

N-(2-(4- ((1R,3R)-2- (2,3-difluoro- propyl)- 3-methyl- 2,3,4,9- tetrahydro-1H- pyrido[3,4- b]indol-1-yl)- 3,5-difluoro- phenoxy) ethyl)-3- fluoropropan- 1-amine ¹H NMR (500 MHz, CDCl₃, 27° C.) 1.16 (3H, d), 1.86-1.98 (2H, m), 2.63-2.72 (2H, m), 2.85 (2H, t), 2.96-3.08 (4H, m), 3.50 (1H, d), 4.05 (2H, t), 4.25-4.78 (5H, m), 5.16 (1H, s), 6.44 (1H, s), 6.46 (1H, s), 7.11 (2H, pd), 7.24 (1H, d), 7.45 (1H, s), 7.51 (1H, d). 496 17

3-((1R,3R)-1- (2,6-difluoro- 4-(2-((3- fluoropropyl) amino)ethoxy) phenyl)-3- methyl- 1,3,4,9- tetrahydro-2H- pyrido[3,4- b]indol-2-yl)- 2-fluoro-2- methylpropan- 1-ol ¹H NMR (500 MHz, CDCl₃, 27° C.) 1.15- 1.23 (6H, m), 1.90 (2H, dddd), 2.64 (1H, dd), 2.82 (3H, t), 2.96-3.03 (4H, m), 3.56-3.72 (3H, m), 3.95-4.05 (2H, m), 4.50 (1H, t), 4.59 (1H, t), 5.34 (1H, s), 6.40-6.48 (2H, m), 7.08-7.16 (2H, m), 7.24 (1H, dt), 7.49- 7.54 (1H, m), 7.57 (1H, s). 508 18

3-((1R,3R)-1- (2,6-difluoro- 4-(2-((3- fluoropropyl) amino)ethoxy) phenyl)-3- methyl- 1,3,4,9- tetrahydro-2H- pyrido[3,4- b]indol-2-yl)- 2-fluoro-2- methylpropan- 1-ol ¹H NMR (500 MHz, CDCl₃, 27° C.) 1.07- 1.15 (6H, m), 1.88 (1H, ddd), 1.93 (1H, ddd), 2.57 (1H, dd), 2.67 (1H, d), 2.83 (2H, t), 2.98- 3.06 (2H, m), 3.13- 3.24 (2H, m), 3.41 (1H, dd), 3.60 (1H, td), 4.03 (3H, t), 4.50 (1H, t), 4.60 (1H, t), 5.04 (1H, s), 6.49 (2H, d), 7.07- 7.14 (2H, m), 7.19- 7.22 (1H, m), 7.40 (1H, s), 7.49-7.53 (1H, m). 508 19

2-(3,5- difluoro-4- ((1R,3R)-2-(2- fluoro-2- methylpropyl)- 3-methyl- 2,3,4,9- tetrahydro-1H- pyrido[3,4- b]indol-1- yl)phenoxy)- N-(3-fluoro- propyl)propan- 1-amine ¹H NMR (500 MHz, DMSO 27° C.) 1.03 (3H, d), 1.09-1.23 (9H, m), 1.68-1.80 (2H, m), 2.29- 2.38 (1H, m), 2.5-2.57 (2H, m), 2.58-2.64 (3H, m), 2.70-2.90 (3H, m), 3.49 (1H, d), 4.42 (1H, td), 4.51 (2H, td), 5.11 (1H, s), 6.64 (2H, d), 6.93 (1H, td), 6.96-7.00 (1H, m), 7.15- 7.19 (1H, m), 7.38 (1H, d), 10.51 (1H, s). 506 20

3-(3,5- difluoro-4- ((1R,3R)-2-(2- fluoro-2-methyl- propyl)-3- methyl-2,3,4,9- tetrahydro-1H- pyrido[3,4- b]indol-1- yl)phenoxy)-2- ((3-fluoro- propyl)amino) propan-1-ol ¹H NMR (500 MHz, CDCl₃, 27° C.) 1.09 (3H, d), 1.14-1.26 (6H, m), 1.88 (2H, dp), 2.39 (1H, dd), 2.60 (2H, dd), 2.74- 2.97 (3H, m), 3.05 (2H, ddt), 3.54 (1H, dd), 3.59- 3.69 (1H, m), 3.72 (1H, dd), 3.91 (1H, ddd), 3.96 (1H, ddd), 4.48 (1H, t), 4.58 (1H, t), 5.19 (1H, s), 6.41 (2H, d), 6.96- 7.13 (2H, m), 7.13-7.22 (1H, m), 7.50 (1H, dd), 7.56 (1H, s). 522 21

3-fluoro-N-(2- (3-fluoro-4- ((1R,3R)-2-((1- fluorocyclo- propyl)methyl)- 3-methyl- 2,3,4,9- tetrahydro-1H- pyrido[3,4- b]indol-1- yl)phenoxy) ethyl)propan- 1-amine ¹H NMR (300 MHz, DMSO-d6) 0.52-0.74 (m, 2H) 0.82-1.02 (m, 2H) 1.06 (d, 3H) 1.59- 1.93 (m, 3H) 2.53- 2.94 (m, 7H) 2.97- 3.18 (m, 1H) 3.32- 3.49 (m, 1H) 4.00 (t, 2H) 4.41 (t, 1H) 4.57 (t, 1H) 5.29 (s, 1H) 6.58- 6.73 (m, 2H) 6.84 (dd, 1H) 6.91-7.08 (m, 2H) 7.17-7.26 (m, 1H) 7.43 (d, 1H) 10.53 (s, 1H) 472 22

3-fluoro-N-(2- (3-fluoro-4- ((1R,3R)-2-((3- fluorooxetan- 3-yl)methyl)- 3-methyl- 2,3,4,9- tetrahydro-1H- pyrido[3,4- b]indol-1- yl)phenoxy) ethyl)propan- 1-amine ¹H NMR (500 MHz, CDCl₃, 27° C.) 1.17 (3H, d), 1.82-1.88 (1H, m), 1.88-1.96 (1H, m), 2.60 (1H, ddd), 2.76-2.87 (3H, m), 2.92 (1H, ddd), 2.96- 3.01 (2H, m), 3.15 (1H, dd), 3.32-3.43 (1H, m), 4.02 (2H, t), 4.36 (1H, dd), 4.48 (1H, t), 4.53- 4.60 (1H, m), 4.66 (2H, ddd), 4.78 (1H, dd), 5.32 (1H, s), 6.51 (1H, dd), 6.66 (1H, dd), 6.75 (1H, t), 7.09-7.14 (1H, m), 7.14- 7.18 (1H, m), 7.25-7.28 (1H, m), 7.49-7.6 (1H, m,) 7.68 (1H, s). 488 23

3-fluoro-N-(2- (4-((1R,3R)-2- ((1-fluoro- cyclopropyl) methyl)-3- methyl- 2,3,4,9- tetrahydro-1H- pyrido[3,4- b]indol-1- yl)phenoxy) ethyl)propan- 1-amine ¹H NMR (300 MHz, DMSO-d6) 0.53-0.72 (m, 2H) 0.91-1.15 (m. 5H) 1.62-1.91 (m, 3H) 2.57-2.77 (m, 4H) 2.85 (br t, 2H) 2.94- 3.12 (m, 1H) 3.20- 3.29 (m, 1H) 3.97 (t, 2H) 4.42 (t, 1H) 4.57 (t, 1H) 5.01 (s, 1H) 6.88 (d, 2H) 6.92-7.07 (m, 2H) 7.15 (d, 2H) 7.25 (d, 1H) 7.42 (d, 1H) 10.61 (s, 1H). 454 24

3-fluoro-N-(2- (4-((1R,3R)-2- ((3- fluorooxetan- 3-yl)methyl)- 3-methyl- 2,3,4,9- tetrahydro-1H- pyrido[3,4- b]indol-1- yl)phenoxy) ethyl)propan- 1-amine ¹H NMR (500 MHz, CDCl₃, 27° C.) 1.14 (3H, d), 1.89 (2H, dddd), 2.51-2.62 (1H, m), 2.75-2.84 (3H, m), 2.91 (1H, ddd), 2.95- 3.04 (2H, m), 3.12 (1H, dd), 3.26-3.38 (1H, m), 4.03 (2H, t), 4.35 (1H, dd), 4.47 (1H, t), 4.56 (1H, d), 4.58-4.73 (2H, m), 4.79 (1H, dd), 4.94 (1H, s), 6.79-6.82 (2H, m), 7.05-7.18 (4H, m), 7.21-7.26 (1H, m), 7.51-7.57 (1H, m), 7.78 (1H, s). 470 25

N-(2-(4- ((1R,3R)-2- (2,3-difluoro- propyl)- 3-methyl- 2,3,4,9- tetrahydro-1H- pyrido[3,4- b]indol-1- yl)phenoxy) ethyl)-3- fluoropropan- 1-amine ¹H NMR (500 MHz, CDCl₃, 27° C.) 1.13 (3H, d), 1.85-1.96 (2H, m), 2.63 (1H, dd), 2.68-2.77 (1H, m), 2.83 (2H, t), 2.89-2.98 (2H, m), 2.99-3.03 (2H, m), 3.38-3.45 (1H, m), 4.06 (2H, t), 4.35-4.74 (5H, m), 4.78 (1H, s), 6.82-6.86 (2H, m), 7.09-7.19 (4H, m), 7.22-7.25 (1H, m), 7.42 (1H, s), 7.51-7.54 (1H, m). 460 26

N-(2-(4- ((1R,3R)-2- (2,3-difluoro- propyl)- 3-methyl- 2,3,4,9- tetrahydro-1H- pyrido[3,4- b]indol-1- yl)phenoxy) ethyl)-3- fluoropropan- 1-amine ¹H NMR (500 MHz, CDCl₃, 27° C.) 1.12 (3H, d), 1.85-1.96 (2H, m), 2.61 (1H, dd), 2.74 (1H, td), 2.83 (2H, t), 2.93-3.03 (4H, m), 3.38-3.45 (1H, m), 4.06 (2H, t), 4.35-4.71 (5H, m), 4.76 (1H, s), 6.82-6.86 (2H, m), 7.09-7.18 (4H, m), 7.22-7.25 (1H, m), 7.41 (1H, s), 7.5-7.54 (1H, m). 460 27

3-fluoro-N- ((S)-1-(4- ((1R,3R)-2-((3- fluorooxetan- 3-yl)methyl)-3- methyl-2,3,4,9- tetrahydro- 1H-pyrido[3,4- b]indol-1- yl)phenoxy) propan-2- yl)propan-1- amine ¹H NMR (500 MHz, CDCl₃, 27° C.) 1.15 (6H, d), 1.80-1.96 (2H, m), 2.59 (1H, dd), 2.72- 2.98 (4H, m), 3.03-3.20 (2H, m), 3.30-3.40 (1H, m), 3.77-3.9 (2H, m), 4.37 (1H, dd), 4.49 (1H, t), 4.55-4.64 (2H, m), 4.69 (1H, dd), 4.80 (1H, dd), 4.94 (1H, s), 6.75- 6.87 (2H, m), 7.08-7.21 (4H, m), 7.27 (1H, s), 7.48-7.62 (2H, m). 484 28

3-fluoro-N- ((R)-1-(4- ((1R,3R)-2-((3- fluorooxetan- 3-yl)methyl)-3- methyl-2,3,4,9- tetrahydro-1H- pyrido[3,4- b]indol-1- yl)phenoxy) propan-2- yl)propan-1- amine ¹H NMR (500 MHz, CDCl₃, 27° C.) 1.12- 1.18 (6H, m), 1.80-1.95 (2H, m), 2.59 (1H, dd), 2.70-2.98 (4H, m), 3.03- 3.20 (2H, m), 3.27-3.41 (1H, m), 3.75-3.89 (2H, m), 4.36 (1H, dd), 4.49 (1H, t), 4.58 (2H, t), 4.68 (1H, dd), 4.79 (1H, dd), 4.94 (1H, s), 6.77-6.86 (2H, m), 7.09-7.18 (4H, m), 7.27 (1H, s), 7.53 (1H, d), 7.58 (1H, s). 484 29

2-((1R,3R)-2- ((1-fluoro- cyclopropyl) methyl)-3- methyl- 2,3,4,9- tetrahydro-1H- pyrido[3,4- b]indol-1-yl)- 5-(2-((3- fluoropropyl) amino)ethoxy) benzonitrile ¹H NMR (300 MHz, DMSO-d6) 0.36-0.63 (m, 2H) 0.75-1.01 (m, 2H) 1.06 (d, 3H) 1.66- 1.86 (m, 2H) 1.86-2.05 (m, 1H) 2.55-2.74 (m, 4H) 2.86 (t, 2H) 2.92- 3.14 (m, 2H) 3.51-3.73 (m, 1H) 4.06 (t, 2H) 4.42 (t, 1H) 4.58 (t, 1H) 5.07 (s, 1H) 6.99 (dtd, 2H) 7.10-7.27 (m, 3H) 7.33-7.56 (m, 2H) 10.39 (s, 1H) 479 30

3-fluoro-N-(2- ((6-((1S,3R)-2- (2-fluoro-2- methylpropyl)- 3-methyl- 2,3,4,9- tetrahydro-1H- pyrido[3,4- b]indol-1- yl)pyridin-3- yl)oxy)ethyl) propan-1-amine ¹H NMR (500 MHz, CDCl₃, 27° C.) 1.24 (3H, dd), 1.30 (3H, d), 1.40 (3H, d), 1.81-1.97 (2H, m), 2.55- 2.67 (2H, m), 2.71 (1H, d), 2.75- 2.90 (3H, m), 2.99 (2H, t), 3.38 (1H, s), 4.06 (2H, t), 4.48 (1H, t), 4.57 (1H, t), 5.07 (1H, s), 7.05 (1H, td), 7.08-7.15 (1H, m), 7.18 (1H, dd), 7.30 (1H, d), 7.48 (1H, d), 7.62 (1H, d), 8.18 (1H, d), 8.80 (1H, s). 457 31

3-fluoro-N-(2- ((6-((1S,3R)-2- ((1-fluoro- cyclopropyl) methyl)-3- methyl- 2,3,4,9- tetrahydro-1H- pyrido[3,4- b]indol-1- yl)pyridin-3- yl)oxy)ethyl) propan-1-amine ¹H NMR (300 MHz, DMSO-d6) 0.52-0.82 (m, 2H), 0.89-1.02 (m, 2H), 1.06-1.16 (m, 3H), 1.67-1.90 (m, 3H), 2.54-2.80 (m, 5H), 2.82-2.91 (m, 2H), 3.03-3.22 (m, 1H), 3.34-3.45 (m, 1H), 3.98-4.11 (m, 2H), 4.36-4.47 (m, 1H), 4.53-4.62 (m, 1H), 4.99-5.04 (m, 1H), 6.90-7.05 (m, 2H), 7.22-7.28 (m, 1H), 7.28-7.34 (m, 1H), 7.35-7.44 (m, 2H), 8.16-8.25 (m, 1H), 10.45-10.56 (m, 1H) 455 32

3-fluoro-N-(2- ((6-((1S,3R)-2- ((3- fluorooxetan- 3-yl)methyl)- 3-methyl- 2,3,4,9- tetrahydro-1H- pyrido[3,4- b]indol-1- yl)pyridin-3- yl)oxy)ethyl) propan-1-amine ¹H NMR (500 MHz, CDCl₃, 27° C.) 1.30 (3H, d), 1.90 (2H, dddd), 2.65 (1H, ddd), 2.77 (1H, dd), 2.82 (2H, t), 2.91-2.99 (1H, m), 2.99-3.05 (2H, m), 3.26 (1H, dd), 3.35 (1H, ddd), 4.09 (2H, t), 4.44 (1H, dd), 4.49 (1H, t), 4.59 (1H, t), 4.68 (2H, td), 4.76 (1H, dd), 5.06 (1H, s), 7.07 (1H, ddd), 7.13 (1H, ddd), 7.19 (1H, dd), 7.32 (1H, dt), 7.44- 7.51 (2H, m), 8.23 (1H, dd), 8.50 (1H, s). 471 33

3-fluoro-N-(2- ((5-((1R,3R)-2- ((1-fluoro- cyclopropyl) methyl)-3- methyl- 2,3,4,9- tetrahydro-1H- pyrido[3,4- b]indol-1- yl)pyridin-2- yl)oxy)ethyl) propan-1-amine ¹H NMR (300 MHz, DMSO-d6) 0.54-0.69 (m, 2H) 0.94-1.02 (m, 1H) 1.08 (d, 4H) 1.63- 1.88 (m, 3H) 2.53-2.67 (m, 3H) 2.69-2.89 (m, 4H) 2.94-3.12 (m, 1H) 4.20-4.32 (m, 2H) 4.37-4.46 (m, 1H) 4.52-4.61 (m, 1H) 4.97-5.06 (m, 1H) 6.77 (d, 1H) 6.91-7.09 (m, 2H), 7.26 (d, 1H) 7.42 (s, 1H) 7.51 (s, 1H) 7.90-8.03 (m, 1H) 10.58-10.69 (m, 1H) 455 34

3-fluoro-N-(2- ((5-((1R,3R)-2- ((3- fluorooxetan- 3-yl)methyl)- 3-methyl- 2,3,4,9- tetrahydro-1H- pyrido[3,4- b]indol-1- yl)pyridin-2- yl)oxy)ethyl) propan-1-amine ¹H NMR (500 MHz, CDCl₃, 27° C.) 1.17 (3H, d), 1.86 (1H, ddd), 1.89- 1.95 (1H, m), 2.53-2.66 (1H, m), 2.74-2.84 (3H, m), 2.93 (1H, ddd), 2.97- 3.03 (2H, m), 3.16 (1H, dd), 3.22-3.32 (1H, m), 4.29-4.43 (3H, m), 4.48 (1H, t), 4.57 (1H, t), 4.64 (1H, dd), 4.70 (1H, dd), 4.83 (1H, dd), 4.99 (1H, s), 6.61-6.70 (1H, m), 7.12 (1H, ddd), 7.14-7.20 (1H, m), 7.27 (1H, dt), 7.37-7.46 (1H, m), 7.50- 7.56 (1H, m), 7.75 (1H, s), 7.94 (1H, d). 471 35

3-fluoro-N-(2- ((6-((1S,3R)-2- (2-fluoro-2- methylpropyl)- 3-methyl- 2,3,4,9- tetrahydro-1H- pyrido[3,4- b]indol-1-yl)- 5-methoxy- pyridin-3- yl)oxy)ethyl) propan-1-amine ¹H NMR (500 MHz, CDCl₃, 27° C.) 1.18 (3H, d), 1.30 (3H, d), 1.36 (3H, d), 1.85 (2H, dddd), 2.49 (1H, dd), 2.60 (1H, ddd), 2.76 (2H, t), 2.78-2.88 (2H, m), 2.87-2.95 (2H, m), 3.55 (1H, d), 3.91-4.00 (2H, m), 4.04 (3H, s), 4.44 (1H, t), 4.54 1H, t), 5.24 (1H, s), 7.04- 7.15 (2H, m), 7.17 (1H, d), 7.27 (1H, d), 7.44- 7.54 (1H, m), 7.67 (1H, d), 8.27 (1H, s) 487 36

3-fluoro-N-(2- ((5-((1R,3R)-2- (2-fluoro-2- methylpropyl)- 3-methyl- 2,3,4,9- tetrahydro-1H- pyrido[3,4- b]indol-1-yl)- 4-methoxy- pyridin-2- yl)oxy)ethyl) propan-1-amine ¹H NMR (500 MHz, CDCl₃, 27° C.) 1.13 (3H, d), 1.29 (3H, d), 1.39 (3H, d), 1.82-1.92 (2H, m), 2.48-2.61 (2H, m), 2.61-2.81 (4H, m), 2.90-3.05 (2H, m), 3.30-3.58 (2H, m), 3.91 (3H, s), 4.34 (2H, ddd), 4.47 (1H, t), 4.56 (1H, s), 5.28 (1H, d), 6.25 (1H, s), 7.01-7.17 (2H, m), 7.23 (1H, dt), 7.45- 7.53 (1H, m), 7.62 (1H, s), 7.92 (1H, s). 487 37

3-fluoro-N-(2- ((5-((1R,3R)-2- ((1-fluoro- cyclopropyl) methyl)-3- methyl- 2,3,4,9- tetrahydro-1H- pyrido[3,4- b]indol-1-yl)- 4-methoxy- pyridin-2- yl)oxy)ethyl) propan-1-amine ¹H NMR (500 MHz, CD₂Cl₂) 0.52-0.71 (m, 2H), 0.92-1.08 (m, 2H), 1.13 (d, 3H), 1.79- 1.93 (m, 2H), 2.61 (dd, 1H), 2.67-2.81 (m, 3H), 2.85-2.92 (m, 1H), 2.94 (br t, 2H), 3.10 (dd, 1H), 3.58- 3.68 (m, 1H), 3.94 (s, 3H), 4.32 (t, 2H), 4.50 (dt, 2H), 5.29 (s, 1H), 6.30 (s, 1H), 6.99- 7.14 (m, 2H), 7.24 (d, 1H), 7.48 (d, 1H), 7.67 (s, 1H), 7.78 (s, 1H) 485 38

3-fluoro-N-(2- ((5-((1S,3R)-2- (2-fluoro-2- methylpropyl)- 3-methyl- 2,3,4,9- tetrahydro-1H- pyrido[3,4- b]indol-1- yl)pyrazin-2- yl)oxy)ethyl) propan-1-amine ¹H NMR (500 MHz, CDCl₃, 27° C.) 1.30 (3H, d), 1.33 (3H, d), 1.48 (3H, d), 1.89 (2H, dddd), 2.63 (2H, d), 2.74 (2H, dd), 2.82 (2H, t), 2.99-3.04 (2H, m), 3.25-3.38 (1H, m), 4.38-4.46 (2H, m), 4.49 (1H, t), 4.58 (1H, t), 5.20 (1H, s), 7.07 (1H, ddd), 7.15 (1H, ddd), 7.36 (1H, d), 7.48 (1H, d), 8.15 (1H, d), 8.50 (1H, s), 8.55 (1H, s). 458 39

3-fluoro-N-(2- ((2-((1S,3R)-2- (2-fluoro-2- methylpropyl)- 3-methyl- 2,3,4,9- tetrahydro-1H- pyrido[3,4- b]indol-1- yl)pyrimidin- 5-yl)oxy)ethyl) propan-1-amine 1H NMR (500 MHz, CDCl₃, 27° C.) 1.25 (3H, d), 1.33 (3H, d), 1.43 (3H, d), 1.75-2.04 (2H, m), 2.51- 2.77 (4H, m), 2.82 (2H, t), 2.95-3.13 (2H, m), 3.77 (1H, s), 4.06-4.15 (2H, m), 4.49 (1H, t), 4.58 (1H, t), 5.33 (1H, s), 7.06 (1H, ddd), 7.08-7.20 (1H, m), 7.28 (1H, dt), 7.43-7.61 (1H, m), 8.32 (1H, s), 8.37 (2H, s). 458

Example 40 Preparation of N-(2-((5-((1R,3R)-2-(2,2-difluoroethyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)-4-methoxypyridin-2-yl)oxy)ethyl)-3-fluoropropan-1-amine

Trifluoroacetic acid (1.64 mL, 21.46 mmol) was added dropwise to a solution of tert-butyl (2-((5-((1R,3R)-2-(2,2-difluoroethyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)-4-methoxypyridin-2-yl)oxy)ethyl)(3-fluoropropyl)carbamate (0.825 g, 1.43 mmol) in DCM (12.7 mL) at 0° C. The resulting mixture was allowed to warm to room temperature and stirred at this temperature for 3 hours. The solution was concentrated under reduced pressure, then the residue was taken up in DCM (20 mL) and washed with saturated aqueous NaHCO₃ (10 mL). The phases were separated and the aqueous phase was extracted with DCM (2×10 mL). The combined organics were dried over Na₂SO₄, filtered and evaporated. The crude residue was purified by preparative HPLC (Waters CSH C18 OBD column, 5μ silica, 30 mm diameter, 100 mm length), using decreasingly polar mixtures of water (containing 0.1% NH₃ and MeCN as eluents. Fractions containing product were evaporated to dryness to afford N-(2-((5-((1R,3R)-2-(2,2-difluoroethyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)-4-methoxypyridin-2-yl)oxy)ethyl)-3-fluoropropan-1-amine (0.365 g, 54%) as a colourless foam. ¹H NMR (500 MHz, CDCl₃, 27° C.) 1.16 (3H, d), 1.80-1.96 (2H, m), 2.56 (1H, dd), 2.69-2.83 (4H, m), 2.94-3.00 (2H, m), 3.06 (1H, qd), 3.30-3.43 (1H, m), 3.94 (3H, s), 4.35 (2H, ddd), 4.48 (1H, t), 4.57 (1H, t), 5.17 (1H, s), 5.80-6.07 (1H, m), 6.28 (1H, s), 7.09-7.18 (2H, m), 7.23-7.26 (1H, m), 7.46 (1H, s), 7.51 (1H, d), 7.61 (1H, s); m/z: ES+ [M+H]+ 477.

The tert-butyl (2-((5-((1R,3R)-2-(2,2-difluoroethyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)-4-methoxypyridin-2-yl)oxy)ethyl)(3-fluoropropyl)carbamate used as starting material was prepared as follows;

Preparation of 2,2-difluoroethyl trifluoromethanesulfonate

Trifluoromethanesulfonic anhydride (17.66 mL, 105.0 mmol) was added to a cooled solution of 2,2-difluoroethane-1-ol (6.33 mL, 100 mmol) in DCM (194 mL) at 0° C. 2,6-Dimethylpyridine (12.81 mL, 110.0 mmol) was added dropwise in DCM (20 mL) and the reaction was stirred at 0° C. for 1 hour. The reaction mixture was washed with 2N HCl (200 mL) and saturated aqueous sodium chloride (100 mL). The organic phase was dried over Na₂SO₄ and filtered, then used directly in solution (approx 0.4M in DCM).

Preparation of (R)—N-(2,2-difluoroethyl)-1-(1H-indol-3-yl)propan-2-amine

2,2-Difluoroethyl trifluoromethanesulfonate (˜0.4M in DCM, 253 mL, 101 mmol) was added dropwise over 10 minutes to a stirred solution of (R)-1-(1H-indol-3-yl)propan-2-amine (16 g, 91.82 mmol) and DIPEA (19.83 mL, 114.78 mmol) in 1,4-dioxane (95 mL). The reaction was stirred at room temperature overnight, then was washed with brine, dried over MgSO₄, filtered and evaporated. The crude product was purified by flash silica chromatography, elution gradient 20 to 50% EtOAc in heptane. Product containing fractions were evaporated to dryness to afford (R)—N-(2,2-difluoroethyl)-1-(1H-indol-3-yl)propan-2-amine (20.94 g, 96%) as a pale yellow oil. ¹H NMR (500 MHz, CDCl₃, 27° C.) 1.13 (3H, d), 2.75-3.18 (5H, m), 5.78 (1H, tt), 7.04 (1H, d), 7.12 (1H, ddd), 7.20 (1H, ddd), 7.36 (1H, dt), 7.60 (1H, dd), 8.02 (1H, s); m/z: ES+ [M+H]+ 239.

Preparation of (1R,3R)-1-(6-chloro-4-methoxypyridin-3-yl)-2-(2,2-difluoroethyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole

(R)—N-(2,2-difluoroethyl)-1-(1H-indol-3-yl)propan-2-amine (0.505 g, 2.12 mmol) and 6-chloro-4-methoxynicotinaldehyde (0.400 g, 2.33 mmol) were dissolved in toluene (9 mL) and AcOH (1 mL). The reaction was warmed to 90° C. under nitrogen for 2.5 hours and then allowed to cool to room temperature. The reaction mixture was basified with saturated aqueous NaHCO₃ then extracted with EtOAc (2×50 mL). The combined organic phases were washed with saturated aqueous sodium chloride and then dried over MgSO₄, filtered and evaporated. The crude product was purified by flash silica chromatography, elution gradient 0 to 25% EtOAc in heptane. Pure fractions were evaporated to dryness to afford (1R,3R)-1-(6-chloro-4-methoxypyridin-3-yl)-2-(2,2-difluoroethyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole (0.825 g, 99%) as a colourless solid. ¹H NMR (500 MHz, CDCl₃, 27° C.) 1.16 (3H, d), 2.57 (1H, ddd), 2.73 (1H, qd), 2.81 (1H, dd), 3.07 (1H, qd), 3.26-3.36 (1H, m), 4.00 (3H, s), 5.21 (1H, s), 5.79-6.06 (1H, m), 6.88 (1H, s), 7.13 (1H, ddd), 7.17 (1H, ddd), 7.24-7.27 (1H, m), 7.51-7.55 (1H, m), 7.66 (1H, s), 7.68 (1H, s); m/z: ES+ [M+H]+ 392.

Preparation of tert-butyl (2-((5-((1R,3R)-2-(2,2-difluoroethyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)-4-methoxypyridin-2-yl)oxy)ethyl)(3-fluoropropyl)carbamate

(1R,3R)-1-(6-chloro-4-methoxypyridin-3-yl)-2-(2,2-difluoroethyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole (0.775 g, 1.98 mmol), cesium carbonate (1.61 g, 4.94 mmol) and RockPhos 3rd generation precatalyst (0.168 g, 0.20 mmol) were charged to a flask which was evacuated and back-filled with nitrogen. A solution of tert-butyl (3-fluoropropyl)(2-hydroxyethyl)carbamate (0.963 g, 4.35 mmol) in degassed toluene (19.8 mL) was added. The vessel was filled with nitrogen and the reaction was stirred vigorously at 90° C. overnight. An additional portion of RockPhos 3rd generation precatalyst (0.168 g, 0.20 mmol) was added and the reaction was stirred vigorously at 90° C. for a further 3 hours. After cooling to room temperature, the reaction was partitioned between water (50 mL) and ethyl acetate (50 mL). The layers were separated and the organic phase was dried over MgSO₄, filtered and evaporated. The crude product was purified by flash silica chromatography, elution gradient 0 to 50% EtOAc in heptane. Product containing fractions were evaporated to dryness to afford tert-butyl (2-((5-((1R,3R)-2-(2,2-difluoroethyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)-4-methoxypyridin-2-yl)oxy)ethyl)(3-fluoropropyl)carbamate (0.825 g, 72%) as a colourless gum. ¹H NMR (500 MHz, CDCl₃, 27° C.) 1.16 (3H, d), 1.37-1.47 (9H, m), 1.94 (2H, s), 2.55 (1H, dd), 2.69-2.83 (2H, m), 3.06 (1H, qd), 3.34-3.42 (3H, m), 3.50-3.63 (2H, m), 3.93 (3H, s), 4.39 (3H, d), 4.51 (1H, s), 5.17 (1H, s), 5.93 (1H, tdd), 6.25 (1H, s), 7.08-7.17 (2H, m), 7.24 (1H, d), 7.44 (1H, s), 7.51 (1H, d), 7.64 (1H, s); m/z: ES+ [M+H]+ 577.

Example 40: (Alternative Route I) Preparation of N-(2-((5-((1R,3R)-2-(2,2-difluoroethyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)-4-methoxypyridin-2-yl)oxy)ethyl)-3-fluoropropan-1-amine

60% sodium hydride in mineral oil (2.48 g, 61.9 mmol) was added portionwise to a stirred solution of 2-((3-fluoropropyl)amino)ethan-1-ol (7.50 g, 61.9 mmol) in THF (103 mL) at 5° C. under nitrogen. The resulting mixture was stirred at 5° C. for 10 minutes. (1R,3R)-1-(6-chloro-4-methoxypyridin-3-yl)-2-(2,2-difluoroethyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole (12.13 g, 30.95 mmol) was added and the mixture was heated to reflux and stirred at reflux for 16 hours. After cooling to room temperature, water (100 mL) was carefully added, followed by EtOAc (200 mL). The layers were separated and the aqueous layer was extracted with EtOAc (3×200 mL). The combined organic extracts were washed with saturated brine (300 mL), filtered through a phase separator cartridge and concentrated under reduced pressure to give the crude product as a pale yellow gum. The crude product was purified by flash silica chromatography, elution gradient 0 to 15% 1M NH₃/MeOH in DCM. Product containing fractions were evaporated to dryness to afford a white solid. The diastereoisomers were separated using the following SFC conditions: Column: Chiralcel OJ-H, 20×250 mm, 5 micron; Mobile phase: 15% MeOH+0.1% NH₃/85% scCO₂; Flow rate 60 mL/min; Detection: UV @ 220 nm. Two peaks were observed, and the main peak was collected and concentrated under reduced pressure to give an off white foam. 10% MeOH in water (100 mL) was added and the resulting mixture was stirred for 16 hours at 21° C. The resulting solid was collected by filtration and washed with 10% MeOH in water (10 mL). The resulting solid was dried under vacuum at 45° C. for 16 hours to give N-(2-((5-((1R,3R)-2-(2,2-difluoroethyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)-4-methoxypyridin-2-yl)oxy)ethyl)-3-fluoropropan-1-amine (7.96 g, 54%) as an off white solid. ¹H NMR (500 MHz, CDCl₃, 27° C.) 1.16 (3H, d), 1.80-1.96 (2H, m), 2.56 (1H, dd), 2.69-2.83 (4H, m), 2.94-3.00 (2H, m), 3.06 (1H, qd), 3.30-3.43 (1H, m), 3.94 (3H, s), 4.35 (2H, ddd), 4.48 (1H, t), 4.57 (1H, t), 5.17 (1H, s), 5.80-6.07 (1H, m), 6.28 (1H, s), 7.09-7.18 (2H, m), 7.23-7.26 (1H, m), 7.46 (1H, s), 7.51 (1H, d), 7.61 (1H, s); m/z: ES+ [M+H]+ 477.

Preparation of 2-((3-fluoropropyl)amino)ethan-1-ol

1-fluoro-3-iodopropane (20.00 g, 106.4 mmol) was added dropwise to a suspension of 2-aminoethane-1-ol (64.20 mL, 1063.9 mmol) and potassium carbonate (53.00 g, 384.1 mmol) in acetonitrile (200 mL) at room temperature and the resulting mixture was stirred at room temperature for 16 hours. The mixture was concentrated under reduced pressure and water (300 mL) was added and the mixture was extracted with DCM (4×500 mL). The combined organic extracts were dried (Na₂SO₄), filtered and concentrated under reduced pressure to give the crude product as a colourless oil. The crude product was purified by filtration through a plug of silica, eluting with 5% MeOH in DCM (2×200 mL) and then 15% 1M NH₃/MeOH in DCM (8×200 mL). The fractions containing the desired material were concentrated under reduced pressure to give 2-((3-fluoropropyl)amino)ethan-1-ol (8.27 g, 64%) as a colourless oil. ¹H NMR (500 MHz, CDCl³, 27° C.) 1.89 (2H, dtt), 2.77-2.82 (4H, m), 3.63-3.69 (2H, m), 4.50 (1H, t), 4.59 (1H, t).

Preparation of (1R,3R)-1-(6-chloro-4-methoxypyridin-3-yl)-2-(2,2-difluoroethyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole

A stirred solution of (R)—N-(2,2-difluoroethyl)-1-(1H-indol-3-yl)propan-2-amine (17.50 g, 73.44 mmol) and 6-chloro-4-methoxynicotinaldehyde (13.23 g, 77.11 mmol) in a mixture of toluene (264 mL) and acetic acid (29 mL) were heated at 85° C. for 2 hours. After cooling, the mixture was concentrated under reduced pressure. The residue was dissolved in DCM (200 mL) and washed with saturated aqueous NaHCO₃ (200 mL). The organic layer was dried over MgSO₄, filtered and evaporated to give a gum. The residue was dissolved in DCM (100 mL) and evaporated to give a yellow/orange solid. The solid was triturated in cold (5° C.) DCM (75 mL) and filtered. The solids were washed with cold DCM (15 mL), then dried to afford the 1^(st) crop of (1R,3R)-1-(6-chloro-4-methoxypyridin-3-yl)-2-(2,2-difluoroethyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole as a colourless solid (˜18 g). The combined filtrates were purified by flash silica chromatography, elution gradient 10 to 50% EtOAc in heptane. Pure fractions were evaporated to dryness and combined with the solids initially collected to afford (1R,3R)-1-(6-chloro-4-methoxypyridin-3-yl)-2-(2,2-difluoroethyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole (26.3 g, 91%) as a beige solid. The sample contained about 7% of the cis isomer by ¹H NMR analysis. ¹H NMR (500 MHz, CDCl₃, 27° C.) 1.16 (3H, d), 2.57 (1H, ddd), 2.73 (1H, qd), 2.81 (1H, dd), 3.07 (1H, qd), 3.26-3.36 (1H, m), 4.00 (3H, s), 5.21 (1H, s), 5.79-6.06 (1H, m), 6.88 (1H, s), 7.13 (1H, ddd), 7.17 (1H, ddd), 7.24-7.27 (1H, m), 7.51-7.55 (1H, m), 7.66 (1H, s), 7.68 (1H, s); m/z: ES+ [M+H]+ 392.

Example 40: (Alternative Route II) Preparation of N-(2-((5-((1R,3R)-2-(2,2-difluoroethyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)-4-methoxypyridin-2-yl)oxy)ethyl)-3-fluoropropan-1-amine

A solution of (R)—N-(2,2-difluoroethyl)-1-(1H-indol-3-yl)propan-2-amine (0.24 g, 1.1 mmol) and 6-(2-((3-fluoropropyl)amino)ethoxy)-4-methoxynicotinaldehyde (0.284 g, 1.11 mmol) in toluene (5 mL) and acetic acid (0.5 mL) was stirred at 100° C. for 1.5 hours and then concentrated under reduced pressure. The residue was treated with saturated aqueous sodium hydrogencarbonate and extracted with ethyl acetate. The extract was dried over anhydrous sodium sulfate, filtered and concentrated under reduced pressure. The resulting residue was purified by flash silica chromatography, eluting gradient 0 to 10% methanol in methylene chloride, to afford N-(2-((5-((1R,3R)-2-(2,2-difluoroethyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)-4-methoxypyridin-2-yl)oxy)ethyl)-3-fluoropropan-1-amine (0.31 g, 65%) as a pale yellow solid. ¹H NMR (DMSO-d₆, 27° C.) 1.08 (3H, d), 1.58-1.86 (2H, m), 1.95 (1H, br s), 2.43-2.55 (1H, m; obsc by DMSO), 2.56-2.76 (4H, m), 2.81 (2H, t), 2.96-3.13 (1H, m), 3.13-3.26 (1H, m), 3.92 (3H, s), 4.21 (2H, t), 4.33-4.67 (2H, m), 5.18 (1H, s), 5.88-6.37 (1H, m), 6.46 (1H, s), 6.92-7.08 (2H, m), 7.09 (1H, s), 7.18-7.28 (1H, m), 7.45 (1H, d), 10.59 (1H, s). m/z: ES+ [M+H]+ 477.

The 6-(2-((3-fluoropropyl)amino)ethoxy)-4-methoxynicotinaldehyde used as starting material was prepared as follows;

Preparation of 6-chloro-4-methoxynicotinonitrile

4,6-Dichloronicotinonitrile (0.10 g, 0.58 mmol) was added to a suspension of potassium carbonate (0.080 g, 0.58 mmol) in MeOH (5 mL). The resulting mixture was stirred at room temperature for 1 hour and then concentrated under reduced pressure. The resulting residue was extracted with methylene chloride, and the organic layer was concentrated under reduced pressure. The resulting residue was purified by flash silica chromatography, elution gradient 0 to 50% ethyl acetate in hexanes, to afford 6-chloro-4-methoxynicotinonitrile (0.070 g, 72%) as a white solid. ¹H NMR (DMSO-d₆, 27° C.) 4.04 (3H, s), 7.52 (1H, s), 8.71 (1H, s). m/z: ES+ [M+H]+ 169.

Preparation of tert-butyl (2-((5-cyano-4-methoxypyridin-2-yl)oxy)ethyl)(3-fluoropropyl)carbamate

Sodium hydride (60 wt % in mineral oil; 0.185 g, 4.63 mmol) was added to an ice cooled solution of 6-chloro-4-methoxynicotinonitrile (0.60 g, 3.6 mmol) and tert-butyl (3-fluoropropyl)(2-hydroxyethyl)carbamate (0.945 g, 4.27 mmol) in THF (12 mL). The mixture was stirred at 0° C. for 10 minutes and then warmed to room temperature. After 2 hours the resulting mixture was filtered, and the filtrate was concentrated under reduced pressure. The residue was purified by flash silica chromatography, elution gradient 0 to 50% ethyl acetate in hexanes, to afford tert-butyl (2-((5-cyano-4-methoxypyridin-2-yl)oxy)ethyl)(3-fluoropropyl)carbamate (1.0 g, 80%) as a colorless oil. ¹H NMR (DMSO-d₆, 27° C.) 1.26-1.43 (9H, br m), 1.72-1.97 (2H, m), 3.30-3.34 (2H, m; obsc by water), 3.53 (2H, br t), 3.95 (3H, s), 4.40-4.48 (2H, m), 4.45 (2H, dt), 6.62 (1H, br s), 8.49 (1H, s). m/z: ES+ [M+H]+ 354.

Preparation of 6-(2-((3-fluoropropyl)amino)ethoxy)-4-methoxynicotinaldehyde

A mixture of ten-butyl (2-((5-cyano-4-methoxypyridin-2-yl)oxy)ethyl)(3-fluoropropyl)carbamate (1.0 g, 2.6 mmol) and aluminum-nickel alloy (50:50; 1.34 g, 15.3 mmol) in 75% formic acid (12 mL) was stirred at 90° C. for 1 hour. The mixture was then allowed to cool to room temperature and filtered. The filtrate was concentrated under reduced pressure. The resulting residue was treated with saturated aqueous sodium hydrogencarbonate and extracted with ethyl acetate. The organic layer was dried over anhydrous sodium sulfate, filtered, and concentrated under reduced pressure. The resulting residue was purified by flash silica chromatography, eluting gradient 0 to 16% methanol in methylene chloride, to afford 6-(2-((3-fluoropropyl)amino)ethoxy)-4-methoxynicotinaldehyde (0.29 g, 44%) as a colorless oil. ¹H NMR (DMSO-d₆, 27° C.) 1.58-1.89 (2H, m), 1.96 (1H, br s), 2.65 (2H, t), 2.87 (2H, t), 3.93 (3H, s), 4.38 (2H, t), 4.52 (2H, dt), 6.55 (1H, s), 8.43 (1H, s), 10.12 (1H, s). m/z: ES+ [M+H]+ 257.

Polymorphic Form A of the 2-methoxybenzoate salt of N-(2-((5-((1R,3R)-2-(2,2-difluoroethyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)-4-methoxypyridin-2-yl)oxy)ethyl)-3-fluoropropan-1-amine (Polymorph Form A of Salt X)

190.6 mg of N-(2-((5-((1R,3R)-2-(2,2-difluoroethyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)-4-methoxypyridin-2-yl)oxy)ethyl)-3-fluoropropan-1-amine (0.40 mmol) was dissolved in 2.0 ml of MeOH. To this solution was slowly added a solution containing 60.9 mg of 2-methoxybenzoic acid (0.40 mmol) dissolved in 2.0 ml of MeOH. White solid started to precipitate out after addition. The resulting slurry was stirred at ambient temperature for 2 hours. The solid was filtrated and washed with 1.0 ml of MeOH three times. 220.1 mg of white solid (yield: 90%) was obtained after the solid was dried in air for 2 hours.

Form A of the 2-methoxybenzoate salt of N-(2-((5-((1R,3R)-2-(2,2-difluoroethyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)-4-methoxypyridin-2-yl)oxy)ethyl)-3-fluoropropan-1-amine was analyzed by XRPD and the results are tabulated below (Table 1) and shown in FIG. 1.

TABLE 1 XRPD Peaks for Form A Angle (2θ ± 0.2°) Intensity (%) 9.2 100.0 22.8 56.0 27.1 18.9 13.8 16.8 19.7 12.0 18.4 11.1 27.7 10.8 17.3 10.0 21.4 9.4 21.1 8.7

Form A of the 2-methoxybenzoate salt of N-(2-((5-((1R,3R)-2-(2,2-difluoroethyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)-4-methoxypyridin-2-yl)oxy)ethyl)-3-fluoropropan-1-amine was analyzed by thermal techniques. DSC analysis indicated that Form A has an endotherm event of melting/decomposition with an onset at 197° C. and a peak at 198° C., followed by and exotherm event. TGA indicated that Form A exhibits a mass loss of about 0.7% upon heating from about 25° C. to about 100° C. A representative DSC/TGA thermogram of Form A is shown in FIG. 2.

Example 41 Preparation of 3-Fluoro-N-(2-((4-methoxy-5-((1R,3R)-3-methyl-2-(2,2,2-trifluoroethyl)-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)pyridin-2-yl)oxy)ethyl)propan-1-amine

10% Palladium on activated charcoal (23.9 mg, 0.02 mmol) was added to a solution of benzyl (3-fluoropropyl)(2-((4-methoxy-5-((1R,3R)-3-methyl-2-(2,2,2-trifluoroethyl)-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)pyridin-2-yl)oxy)ethyl)carbamate (141 mg, 0.22 mmol) in EtOH (10 mL) under a stream of nitrogen. The mixture was evacuated and backfilled with hydrogen (2×) before stirring at room temperature under an atmosphere of hydrogen for 3 hours. The reaction was filtered through Celite™ washing with MeOH (50 mL). The filtrate was concentrated under reduced pressure and the crude product was purified by preparative LCMS (Waters XSelect CSH C18 column, 5μ silica, 50 mm diameter, 100 mm length), using decreasingly polar mixtures of water (containing 1% NH₃) and MeCN as eluents to afford 3-fluoro-N-(2-((4-methoxy-5-((1R,3R)-3-methyl-2-(2,2,2-trifluoroethyl)-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)pyridin-2-yl)oxy)ethyl)propan-1-amine (35 mg, 32%) as a colourless gum. ¹H NMR (500 MHz, CDCl₃, 27° C.) 1.17 (3H, d), 1.82-1.94 (2H, m), 2.55 (1H, ddd), 2.78-2.83 (3H, m), 2.91-3.00 (3H, m), 3.19-3.29 (1H, m), 3.42-3.49 (1H, m), 3.92 (3H, s), 4.30-4.40 (2H, m), 4.52 (2H, dt), 5.26 (1H, s), 6.27 (1H, s), 7.08-7.12 (1H, m), 7.13-7.17 (1H, m), 7.24 (1H, dt), 7.46 (1H, s), 7.49-7.52 (1H, m), 7.73 (1H, s). (One proton not observed). m/z: ES+ [M+H]+ 456.

The starting benzyl (3-fluoropropyl)(2-((4-methoxy-5-((1R,3R)-3-methyl-2-(2,2,2-trifluoroethyl)-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)pyridin-2-yl)oxy)ethyl)carbamate was prepared as follows:

(R)-1-(1H-Indol-3-yl)-N-(2,2,2-trifluoroethyl)propan-2-amine

Trifluoromethanesulfonic anhydride (5.92 mL, 35.19 mmol), followed by 2,6-dimethylpyridine (4.47 mL, 38.4 mmol) were added to a cooled solution of 2,2,2-trifluoroethan-1-ol (2.33 mL, 32.0 mmol) in dichloromethane (100 mL). The reaction was stirred for 1 hour, then washed with 1N HCl (30 mL). The organic phase was dried over MgSO₄, filtered and carefully concentrated. (400 mbar, 43° C. bath temperature) to afford a red oil. This was added to a solution of (R)-1-(1H-indol-3-yl)propan-2-amine (5.05 g, 29.0 mmol) and DIPEA (7.51 mL, 43.5 mmol) in DCM (100 mL) and the reaction was stirred at room temperature for 16 hours. The reaction mixture was allowed to cool and evaporated under reduced pressure. The crude product was purified by flash silica chromatography, elution gradient 0 to 100% EtOAc in heptane to afford (R)-1-(1H-indol-3-yl)-N-(2,2,2-trifluoroethyl)propan-2-amine (5.84 g, 79%) as a yellow oil. ¹H NMR (500 MHz, CDCl₃, 27° C.) 1.13 (3H, d), 1.47 (1H, s), 2.84 (2H, d), 3.11-3.21 (3H, m), 7.03 (1H, d), 7.12 (1H, ddd), 7.20 (1H, ddd), 7.35 (1H, d), 7.58-7.61 (1H, m), 8.01 (1H, s). m/z: ES+ [M+H]+ 257.

(1R,3R)-1-(6-Chloro-4-methoxypyridin-3-yl)-3-methyl-2-(2,2,2-trifluoroethyl)-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole

Acetic acid (0.667 mL) was added to a solution of (R)-1-(1H-indol-3-yl)-N-(2,2,2-trifluoroethyl)propan-2-amine (0.27 g, 1.05 mmol) and 6-chloro-4-methoxynicotinaldehyde (0.199 g, 1.16 mmol) in toluene (6 mL). The reaction was warmed to 90° C. under nitrogen for 16 hours and then allowed to cool to room temperature. The reaction mixture was basified with saturated NaHCO₃ solution (25 mL) then extracted with EtOAc (75 mL). The organic phase was washed with saturated aqueous sodium chloride and then dried (MgSO₄), filtered and concentrated under reduced pressure. The crude product was purified by flash silica chromatography, elution gradient 0 to 100% EtOAc in heptane to afford (1R,3R)-1-(6-chloro-4-methoxypyridin-3-yl)-3-methyl-2-(2,2,2-trifluoroethyl)-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole (0.425 g, 98%) as a white solid. ¹H NMR (500 MHz, CDCl₃, 27° C.) 1.17 (3H, d), 2.57 (1H, ddd), 2.82 (1H, dd), 2.90-2.99 (1H, m), 3.21-3.30 (1H, m), 3.34-3.41 (1H, m), 3.98 (3H, s), 5.30 (1H, s), 6.87 (1H, s), 7.11-7.15 (1H, m), 7.16-7.2 (1H, m), 7.25-7.28 (1H, m), 7.51-7.54 (1H, m), 7.68 (1H, s), 7.73 (1H, s). m/z: ES+ [M+H]+ 410.

Benzyl (3-fluoropropyl)(2-((4-methoxy-5-((1R,3R)-3-methyl-2-(2,2,2-trifluoroethyl)-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)pyridin-2-yl)oxy)ethyl)carbamate

(1R,3R)-1-(6-Chloro-4-methoxypyridin-3-yl)-3-methyl-2-(2,2,2-tri fluoroethyl)-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole (0.2 g, 0.49 mmol), cesium carbonate (0.397 g, 1.22 mmol) and RockPhos Pd G3 (0.041 g, 0.05 mmol) were charged to a flask and the flask evacuated and back filled with nitrogen. A solution of benzyl (3-fluoropropyl)(2-hydroxyethyl)carbamate (0.249 g, 0.98 mmol) in degassed toluene (4.88 mL) was added and the resulting mixture heated to 90° C. for 2 hours. Two more portions of benzyl (3-fluoropropyl)(2-hydroxyethyl)carbamate (0.249 g, 0.98 mmol) were added over the next 6 hours. After cooling to room temperature, the reaction was filtered through Celite™ and the filtrate was concentrated under reduced pressure. The crude product was purified by flash silica chromatography, elution gradient 0 to 100% EtOAc in heptane to afford benzyl (3-fluoropropyl)(2-((4-methoxy-5-((1R,3R)-3-methyl-2-(2,2,2-trifluoroethyl)-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)pyridin-2-yl)oxy)ethyl)carbamate (0.141 g, 46%) as a beige gum. m/z: ES+ [M+H]+ 629.

Example 42 Preparation of N-(2-((5-((1R,3R)-2-(2,2-Difluoropropyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)-4-methoxypyridin-2-yl)oxy)ethyl)-3-fluoropropan-1-amine

2,2,2-Trifluoroacetic acid (0.470 mL, 6.15 mmol) was added to a solution of tert-butyl (2-((5-((1R,3R)-2-(2,2-difluoropropyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)-4-methoxypyridin-2-yl)oxy)ethyl)(3-fluoropropyl)carbamate (242 mg, 0.41 mmol) in DCM (4.7 mL) at 0° C. and the resulting mixture allowed to warm to room temperature and stirred for 4 hours. The reaction mixture was evaporated under reduced pressure and then the residue was taken up in DCM and washed with saturated aqueous sodium bicarbonate (10 mL). The phases were separated and the aqueous phase was extracted with DCM (2×10 mL). The combined organics were dried (Na₂SO₄) and evaporated under reduced pressure. The crude product was purified by reverse phase HPLC (Waters CSH C18 OBD column, 5μ silica, 30 mm diameter, 100 mm length), using decreasingly polar mixtures of water (containing 0.1% NH₃ and MeCN as eluents to give N-(2-((5-((1R,3R)-2-(2,2-difluoropropyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)-4-methoxypyridin-2-yl)oxy)ethyl)-3-fluoropropan-1-amine (138 mg, 69%) as a colourless foam. ¹H NMR (500 MHz, CDCl₃, 27° C.) 1.15 (3H, d), 1.64 (3H, t), 1.82-1.93 (2H, m), 2.55 (1H, ddd), 2.69-2.81 (4H, m), 2.88-2.98 (3H, m), 3.40-3.48 (1H, m), 3.90 (3H, s), 4.30-4.37 (2H, m), 4.52 (2H, dt), 5.25 (1H, s), 6.25 (1H, s), 7.07-7.11 (1H, m), 7.11-7.15 (1H, m), 7.21-7.24 (1H, m), 7.47 (1H, s), 7.48-7.52 (1H, m), 7.83 (1H, s). (One proton not observed). m/z: ES+ [M+H]+ 491.

The starting benzyl tert-butyl (2-((5-((1R,3R)-2-(2,2-difluoropropyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)-4-methoxypyridin-2-yl)oxy)ethyl)(3-fluoropropyl)carbamate was prepared as follows:

(R)—N-(1-(1H-Indol-3-yl)propan-2-yl)-N-(2,2-difluoropropyl)-2,2-difluoropropan-1-amine

Trifluoromethanesulfonic anhydride (9.34 mL, 55.2 mmol) was added to a solution of 2,2-difluoropropan-1-ol (5.05 g, 52.6 mmol) in DCM (100 mL) at −10° C. followed by dropwise addition of 2,6-dimethylpyridine (7.35 mL, 63.1 mmol) in DCM (50 mL). The reaction was stirred for 1 hour before addition of 2N HCl (150 mL). The layers were separated and the aqueous phase was extracted with DCM (100 mL), then the combined organics were dried and concentrated carefully (no lower than 200 mbar, 40° C.) to afford 2,2-difluoropropyl trifluoromethanesulfonate (12.90 g) as a brown/red oil that was used directly in next stage. 2,2-Difluoropropyl trifluoromethanesulfonate (11.91 g, 52.22 mmol) was added to a solution of (R)-1-(1H-indol-3-yl)propan-2-amine (6.50 g, 37.3 mmol) and DIPEA (12.9 ml, 74.6 mmol) in 1,4-dioxane (75 mL) and the reaction was then heated to 65° C. for 1.5 hours. The reaction was cooled to room temperature and diluted with EtOAc (250 mL). This was washed with water (2×100 mL) and saturated aqueous sodium chloride (100 mL). The organic phase was separated and dried (MgSO₄), filtered and evaporated. The crude product was purified by flash silica chromatography, elution gradient 0 to 10% MeOH in DCM to afford (R)—N-(1-(1H-indol-3-yl)propan-2-yl)-2,2-difluoropropan-1-amine (7.99 g, 85%) as an orange/brown oil. ¹H NMR (500 MHz, CDCl₃, 27° C.) 1.11 (3H, d), 1.58 (3H, t), 2.77-3.00 (4H, m), 3.07 (1H, h), 7.04 (1H, d), 7.12 (1H, ddd), 7.19 (1H, ddd), 7.36 (1H, dt), 7.57-7.62 (1H, m), 8.03 (1H, s). (One proton not observed). m/z: ES+ [M+H]+ 253.

(1R,3R)-1-(6-Chloro-4-methoxypyridin-3-yl)-2-(2,2-difluoropropyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole

A solution of 6-chloro-4-methoxynicotinaldehyde (191 mg, 1.11 mmol), (R)—N-(1-(1H-indol-3-yl)propan-2-yl)-2,2-difluoropropan-1-amine (281 mg, 1.11 mmol) and acetic acid (0.56 mL) in toluene (5.0 mL) were stirred at 100° C. for 4 hours and then at room temperature for 2 days. The volatiles were evaporated under reduced pressure. The residue was dissolved in DCM (50 mL) and washed with saturated aqueous NaHCO₃ (50 mL). The aqueous layer was extracted with DCM (50 mL) and the combined organics were dried and evaporated. The crude product was purified by flash silica chromatography, elution gradient 0 to 25% EtOAc in heptane to afford (1R,3R)-1-(6-chloro-4-methoxypyridin-3-yl)-2-(2,2-difluoropropyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole (364 mg, 81%) as a yellow solid. ¹H NMR (500 MHz, CDCl₃, 27° C.) 1.16 (3H, d), 1.64 (3H, t), 2.57 (1H, ddd), 2.68-2.77 (1H, m), 2.79 (1H, dd), 2.88-3.00 (1H, m), 3.35-3.43 (1H, m), 3.99 (3H, s), 5.32 (1H, s), 6.87 (1H, s), 7.09-7.14 (1H, m), 7.14-7.18 (1H, m), 7.24-7.27 (1H, m), 7.52 (1H, d), 7.69 (1H, s), 7.75 (1H, s). m/z: ES+ [M+H]+ 406.

tert-Butyl (2-((5-((1R,3R)-2-(2,2-difluoropropyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)-4-methoxypyridin-2-yl)oxy)ethyl)(3-fluoropropyl)carbamate

(1R,3R)-1-(6-Chloro-4-methoxypyridin-3-yl)-2-(2,2-difluoropropyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole (214 mg, 0.53 mmol), cesium carbonate (429 mg, 1.32 mmol) and RockPhos 3rd generation (44.7 mg, 0.05 mmol) were charged to a flask and the flask evacuated and back filled with nitrogen. A solution of tert-butyl (3-fluoropropyl)(2-hydroxyethyl)carbamate (257 mg, 1.16 mmol) in degassed toluene (5.3 mL) was added. The vessel was filled with nitrogen and the reaction was stirred vigorously at 90° C. overnight. A second portion of RockPhos 3rd generation (44.7 mg, 0.05 mmol) was added and the reaction was stirred vigorously at 90° C. for a second day. After cooling to room temperature, the reaction was combined with a previous batch which started with 155 mg of the chloro compound. The combined batches were partitioned between water and (50 mL) and ethyl acetate (50 mL). The layers were separated and the organic phase was dried over MgSO₄, filtered and evaporated under reduced pressure. The crude product was purified by flash silica chromatography, elution gradient 0 to 50% EtOAc in heptane to afford tert-butyl (2-((5-((1R,3R)-2-(2,2-difluoropropyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)-4-methoxypyridin-2-yl)oxy)ethyl)(3-fluoropropyl)carbamate (242 mg, 78%) as a colourless gum. ¹H NMR (500 MHz, CDCl₃, 27° C.) 1.16 (3H, d), 1.42 (9H, br d), 1.64 (3H, t), 1.87-2.03 (2H, m), 2.56 (1H, dd), 2.70-2.82 (2H, m), 2.89-2.99 (1H, m), 3.35-3.58 (5H, m), 3.92 (3H, s), 4.35 (2H, s), 4.47 (2H, br d), 5.26 (1H, s), 6.24 (1H, s), 7.10 (1H, td), 7.14 (1H, td), 7.23-7.25 (1H, m), 7.47-7.52 (2H, m), 7.68 (1H, s). m/z: ES+ [M+H]+ 591.

Example 43 Preparation of N-(2-(4-((1R,3R)-2-(2,2-Difluoroethyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)-3-methoxyphenoxy)ethyl)-3-fluoropropan-1-amine

Trifluoroacetic acid (0.285 mL, 3.70 mmol) was added to a stirred solution of tert-butyl (2-(4-((1R,3R)-2-(2,2-difluoroethyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)-3-methoxyphenoxy)ethyl)(3-fluoropropyl)carbamate (142 mg, 0.25 mmol) in DCM (2.0 mL) under nitrogen. After 25 minutes the solution was concentrated under reduced pressure. The residue was taken up in DCM and washed with saturated aqueous sodium bicarbonate. The phases were separated and the aqueous phase extracted with DCM (2×10 mL). The combined organics were dried over MgSO₄, filtered and concentrated under reduced pressure. The crude product was purified by flash silica chromatography to dryness to afford N-(2-(4-((1R,3R)-2-(2,2-difluoroethyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)-3-methoxyphenoxy)ethyl)-3-fluoropropan-1-amine (79 mg, 67%). ¹H NMR (500 MHz, CDCl₃, 27° C.) 1.14 (3H, d), 1.82-1.93 (2H, m), 2.56 (1H, ddd), 2.67-2.82 (3H, m), 2.89 (1H, dd), 2.95-3.05 (3H, m), 3.37-3.45 (1H, m), 3.89 (3H, s), 3.97-4.04 (2H, m), 4.52 (2H, dt), 5.23 (1H, s), 5.82 (1H, tdd), 6.31 (1H, dd), 6.53 (1H, d), 6.82 (1H, d), 7.06 7.13 (2H, m), 7.18-7.21 (1H, m), 7.49-7.52 (1H, m), 7.76 (1H, s). m/z: ES+ [M+H]+ 476.

The starting of tert-butyl (2-(4-((1R,3R)-2-(2,2-difluoroethyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)-3-methoxyphenoxy)ethyl)(3-fluoropropyl)carbamate was prepared as follows:

tert-Butyl (2-(4-((1R,3R)-2-(2,2-Difluoroethyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)-3-methoxyphenoxy)ethyl)(3-fluoropropyl)carbamate

tert-Butyl (3-fluoropropyl)(2-hydroxyethyl)carbamate (229 mg, 1.03 mmol), (1R,3R)-1-(4-bromo-2-methoxyphenyl)-2-(2,2-difluoroethyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole (150 mg, 0.34 mmol), Pd RockPhos 3rd generation (29.2 mg, 0.03 mmol) and cesium carbonate (225 mg, 0.69 mmol) were suspended in toluene (2.9 mL) and sealed into a microwave tube. The reaction was heated, under microwave irradiation, to 100° C. for 4 hours. The reaction mixture was diluted with EtOAc (25 mL), filtered through Celite™ and evaporated to dryness. The crude product was purified by flash silica chromatography, elution gradient 0 to 100% EtOAc in heptane to afford tert-butyl (2-(4-((1R,3R)-2-(2,2-difluoroethyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)-3-methoxyphenoxy)ethyl)(3-fluoropropyl)carbamate (145 mg, 73%) as a pale orange gum. ¹H NMR (500 MHz, CDCl₃, 27° C.) 1.14 (3H, d), 1.44 (9H, s), 1.86-2.02 (2H, m), 2.56 (1H, dd), 2.65-2.79 (1H, m), 2.90 (1H, dd), 3.00 (1H, qd), 3.35-3.47 (3H, m), 3.57 (2H, s), 3.91 (3H, s), 4.00-4.10 (2H, m), 4.38-4.46 (1H, m), 4.49-4.56 (1H, m), 5.24 (1H, s), 5.83 (1H, tdd), 6.31 (1H, d), 6.53 (1H, s), 6.80-6.87 (1H, m), 7.06-7.14 (2H, m), 7.19-7.23 (1H, m), 7.49-7.52 (1H, m), 7.62 (1H, s). m/z: ES+ [M+H]+ 576.

(1R,3R)-1-(4-Bromo-2-methoxyphenyl)-2-(2,2-difluoroethyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole

Acetic acid (1.061 ml) was added to a solution of (R)—N-(2,2-difluoroethyl)-1-(1H-indol-3-yl)propan-2-amine (0.455 g, 1.91 mmol) and 4-bromo-2-methoxybenzaldehyde (0.431 g, 2.00 mmol) in toluene (9.55 mL). The resulting mixture was heated at 90° C. for 16 hours. The mixture was concentrated under reduced pressure. The crude product was purified by flash silica chromatography, elution gradient 5 to 30% EtOAc in heptane to afford (1R,3R)-1-(4-bromo-2-methoxyphenyl)-2-(2,2-difluoroethyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole (0.750 g, 90%) as a white crystalline solid. ¹H NMR (500 MHz, CDCl₃, 27° C.) 1.15 (3H, d), 2.58 (1H, ddd), 2.66-2.78 (1H, m), 2.87-2.92 (1H, m), 2.99-3.09 (1H, m), 3.36-3.43 (1H, m), 3.95 (3H, s), 5.26 (1H, s), 5.86 (1H, tdd), 6.83 (1H, d), 6.96 (1H, dd), 7.09-7.17 (3H, m), 7.23-7.25 (1H, m), 7.5-7.53 (1H, m), 7.57 (1H, s).

Example 44 Preparation of N1-(3,5-difluoro-4-((1R,3R)-2-((3-fluorooxetan-3-yl)methyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)phenyl)-N2-(3-fluoropropyl)ethane-1,2-diamine

Benzyl (2-((3,5-difluoro-4-((1R,3R)-2-((3-fluorooxetan-3-yl)methyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)phenyl)amino)ethyl)(3-fluoropropyl)carbamate (190 mg, 0.30 mmol) was dissolved in ethanol (2 mL) and the reaction flask was evacuated and back-filled with nitrogen. Palladium on carbon (10 wt %; 31 mg, 0.026 mmol) was then added and the mixture was again evacuated and then subjected to a hydrogen atmosphere (balloon) for 1 hour with stirring at ambient temperature. The mixture was then filtered through diatomaceous earth, and the filtrate was concentrated under reduced pressure. The resulting residue was purified by reverse phase chromatography (C18 column), eluting with decreasingly polar mixtures of water and acetonitrile as eluents. Product fractions were concentrated under reduced pressure to afford N1-(3,5-difluoro-4-((1R,3R)-2-((3-fluorooxetan-3-yl)methyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)phenyl)-N2-(3-fluoropropyl)ethane-1,2-diamine (40 mg, 27%) as a white solid. ¹H NMR (500 MHz, DMSO-d₆, 27° C.) 1.09 (3H, d), 1.71-1.84 (2H, m), 2.54-2.57 (2H, m), 2.61 (2H, br t), 2.67 (2H, br t), 2.78-2.85 (2H, m), 3.07 (2H, q), 3.16 (1H, dd), 3.38-3.45 (1H, m), 4.29 (1H, dd), 4.41-4.59 (5H, m), 5.08 (1H, s), 6.16-6.24 (3H, m), 6.91-6.96 (1H, m), 6.96-7.01 (1H, m), 7.19 (1H, d), 7.38 (1H, d), 10.54 (1H, s). m/z: ES+ [M+H]+ 505.

Procedures used to prepare the starting material benzyl (2-((3,5-difluoro-4-((1R,3R)-2-((3-fluorooxetan-3-yl)methyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)phenyl)amino)ethyl)(3-fluoropropyl)carbamate are described below.

Preparation of benzyl (2-((3,5-difluoro-4-((1R,3R)-2-((3-fluorooxetan-3-yl)methyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)phenyl)amino)ethyl)(3-fluoropropyl)carbamate

Potassium carbonate (169 mg, 1.22 mmol) and BrettPhos 3^(rd) Generation Precatalyst (28 mg, 0.030 mmol) were added sequentially to a solution of (1R,3R)-1-(4-bromo-2,6-difluorophenyl)-2-((3-fluorooxetan-3-yl)methyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole (284 mg, 0.61 mmol) and benzyl (2-aminoethyl)(3-fluoropropyl)carbamate (202 mg, 0.79 mmol) in tetrahydrofuran (6.1 mL) that had been degassed via sequential application of vacuum and nitrogen atmosphere (×3). The mixture was warmed to 100° C. After 6 hours, the reaction was cooled, filtered with an ethyl acetate wash, and the filtrate was concentrated under reduced pressure. The resulting residue was purified by flash column chromatography, elution gradient 0 to 50% ethyl acetate in hexanes, to afford a beige foam solid (190 mg, 49%). ¹H NMR (300 MHz, DMSO-d₆, 27° C.) 1.09 (3H, d), 1.76-1.96 (2H, m), 2.52-2.60 (1H, m), 2.68-2.90 (2H, m), 3.07-3.24 (3H, m), 3.32-3.46 (5H, m), 4.24-4.60 (6H, m), 5.05-5.13 (3H, m), 6.11-6.29 (2H, m), 6.34 (1H, br s), 6.90-7.03 (2H, m), 7.16-7.22 (1H, m), 7.23-7.42 (6H, m), 10.52 (1H, s). m/z: ES+ [M+H]+ 639.

Example 45 Preparation of N1-(3,5-difluoro-4-((1R,3R)-2-((1-fluorocyclopropyl)methyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)phenyl)-N2-(3-fluoropropyl)-N1-methylethane-1,2-diamine

Iodomethane (0.059 mL, 0.95 mmol) was added to a solution of benzyl (2-((3,5-difluoro-4-((1R,3R)-2-((1-fluorocyclopropyl)methyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1 yl)phenyl)amino)ethyl)(3-fluoropropyl)carbamate (296 mg, 0.48 mmol) and DIPEA (0.249 mL, 1.43 mmol) in DMF. The reaction was stirred at 50° C. for 18 hours and then diluted with water, extracted with EtOAc (×2), and the combined organic layers were concentrated under reduced pressure. The resulting residue was purified by flash silica chromatography, elution gradient 0 to 50% EtOAc in hexanes. Product fractions were concentrated under reduced pressure to give impure benzyl (2-((3,5-difluoro-4-((1R,3R)-2-((1-fluoro cyclopropyl)methyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)phenyl)(methyl)amino)ethyl)(3-fluoropropyl)carbamate (75 mg). This material was dissolved in ethanol (1 mL) and stirred over 10 wt % palladium on carbon (12 mg, 0.010 mmol) under a hydrogen atmosphere for 35 minutes at ambient temperature. The mixture was then filtered through diatomaceous earth, and the filtrate was concentrated under reduced pressure. The resulting residue was purified by preparative HPLC (Waters XBridge C18 OBD column, 5μ silica, 19 mm diameter, 150 mm length), using decreasingly polar mixtures of water (containing 0.2% NH₄OH) and acetonitrile as eluents. Product fractions were concentrated under reduced pressure to afford N1-(3,5-difluoro-4-((1R,3R)-2-((1-fluorocyclopropyl)methyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)phenyl)-N2-(3-fluoropropyl)-N1-methylethane-1,2-diamine (13 mg, 21%) as an off-white solid. ¹H NMR (400 MHz, DMSO-d₆, 89° C.) 0.50-0.56 (2H, m), 0.89 (2H, d), 1.08 (3H, d), 1.68-1.84 (2H, m), 2.56-2.79 (6H, m), 2.88-2.92 (3H, m), 3.35 (2H, t), 3.57-3.66 (1H, m), 4.47 (2H, dt), 5.14 (1H, s), 6.25 (2H, d), 6.87-7.00 (2H, m), 7.19 (1H, d), 7.37 (1H, d), 10.16 (1H, br s). Three hydrogens obscured by DMSO and water peaks. m/z: ES+ [M+H]+ 503.

Example 46 Preparation of 3-((1R,3R)-1-(2,6-difluoro-4-((2-((3-fluoropropyl)amino)ethyl)amino)phenyl)-3-methyl-1,3,4,9-tetrahydro-2H-pyrido[3,4-b]indol-2-yl)-2,2-difluoropropan-1-ol

Tetrabutylammonium fluoride in tetrahydrofuran (1.0 M; 0.41 mL, 0.41 mmol) was added dropwise to a solution of N1-(4-((1R,3R)-2-(3-((tert-butyldiphenylsilyl)oxy)-2,2-difluoropropyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)-3,5-difluorophenyl)-N2-(3-fluoropropyl)ethane-1,2-diamine (205 mg, 0.27 mmol) in tetrahydrofuran (2.3 mL). After 2 hours, the reaction was diluted with EtOAc, washed with saturated aqueous sodium chloride (25 mL) and the aqueous layer was extracted with EtOAc (×3). The combined organic layers were dried over sodium sulfate, filtered, and adsorbed onto silica gel under reduced pressure before being purified by flash silica chromatography, elution gradient 0 to 10% methanol in dichloromethane. Product fractions were combined and concentrated under reduced pressure. The resulting residue was further purified by reverse-phase chromatography (Column: Teledyne Isco RediSep Rf® Gold Reversed-phase C18) eluting with 0% to 100% acetonitrile in water to afford 3-((1R,3R)-1-(2,6-difluoro-4-((2-((3-fluoropropyl)amino)ethyl)amino)phenyl)-3-methyl-1,3,4,9-tetrahydro-2H-pyrido[3,4-b]indol-2-yl)-2,2-difluoropropan-1-ol (45 mgs, 32%) as a yellow crystalline solid. ¹H NMR (500 MHz, DMSO-d₆, 27° C.) 1.08 (3H, br d), 1.70-1.99 (3H, m), 2.54-2.58 (2H, m), 2.61 (2H, br t), 2.67 (2H, br t), 2.83 (1H, br dd), 3.03-3.14 (3H, m), 3.37-3.50 (2H, m), 3.61-3.75 (1H, m), 4.51 (2H, dt), 5.06 (1H, s), 5.25 (1H, t), 6.14-6.23 (3H, m), 6.91-6.96 (1H, m), 6.97-7.02 (1H, m), 7.19 (1H, d), 7.38 (1H, d), 10.53 (1H, s). m/z: ES+ [M+H]+ 511.

Procedures used to prepare the starting material N1-(4-((1R,3R)-2-(3-((tert-butyldiphenylsilyl)oxy)-2,2-difluoropropyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)-3,5-difluorophenyl)-N2-(3-fluoropropyl)ethane-1,2-diamine are described below.

Benzyl (2-((4-((1R,3R)-2-(3-((tert-butyldiphenylsilyl)oxy)-2,2-difluoropropyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)-3,5-difluorophenyl)amino)ethyl)(3-fluoropropyl)carbamate

Potassium carbonate (156 mg, 1.13 mmol) and BrettPhos 3^(rd) Generation Precatalyst (26 mg, 0.030 mmol) were added sequentially to a solution of (1R,3R)-1-(4-bromo-2,6-difluorophenyl)-2-(3-((tert-butyldiphenylsilyl)oxy)-2,2-difluoropropyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole (400 mg, 0.56 mmol) and benzyl (2-aminoethyl)(3-fluoropropyl)carbamate (186 mg, 0.73 mmol) in tetrahydrofuran (5.6 mL) that had been degassed via sequential application of vacuum and nitrogen atmosphere (×3). The mixture was warmed to 110° C. After 48 hours, the reaction was cooled, filtered with an ethyl acetate wash, and the filtrate was concentrated under reduced pressure. The resulting residue was purified by flash column chromatography, elution gradient 0 to 50% ethyl acetate in hexanes, to afford benzyl (2-((4-((1R,3R)-2-((3-fluorooxetan-3-yl)methyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)-3-methoxyphenyl)amino)ethyl)(3-fluoropropyl)carbamate (260 mgs, 71% yield) as a beige foam solid. m/z: ES+ [M+H]+ 883.

Preparation of benzyl (2-((4-((1R,3R)-2-((3-fluorooxetan-3-yl)methyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)-3-methoxyphenyl)amino)ethyl)(3-fluoropropyl)carbamate

Benzyl (2-((4-((1R,3R)-2-(3-((tert-butyldiphenylsilyl)oxy)-2,2-difluoropropyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)-3,5-difluorophenyl)amino)ethyl)(3-fluoropropyl)carbamate (260 mg, 0.29 mmol) was dissolved in ethanol (2 mL) and the reaction flask was evacuated and backfilled with nitrogen (×2). Palladium on carbon (10 wt %; 31 mg, 0.026 mmol) was then added and the mixture was evacuated and backfilled with hydrogen (balloon), and the mixture was stirred for 1 hour at ambient temperature. The mixture was then filtered through diatomaceous earth, and the filtrate was concentrated under reduced pressure to afford N1-(4-((1R,3R)-2-(3-((tert-butyldiphenylsilyl)oxy)-2,2-difluoropropyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)-3,5-difluorophenyl)-N2-(3-fluoropropyl)ethane-1,2-diamine (205 mg, 93%) as a yellow solid. m/z: ES+ [M+H]+ 749.

Example 47 Preparation of N1-(4-((1R,3R)-2-((3-fluorooxetan-3-yl)methyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)-3-methoxyphenyl)-N2-(3-fluoropropyl)ethane-1,2-diamine

Benzyl (2-((4-((1R,3R)-2-((3-fluorooxetan-3-yl)methyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)-3-methoxyphenyl)amino)ethyl)(3-fluoropropyl)carbamate (234 mg, 0.37 mmol) was dissolved in ethanol (2 mL). The reaction flask was evacuated and backfilled with nitrogen. Palladium on carbon (10 wt %; 40 mg, 0.037 mmol) was then added and the reaction was evacuated and backfilled with hydrogen (balloon), and the reaction was stirred under a hydrogen atmosphere for 1 hour at ambient temperature. The mixture was then filtered through diatomaceous earth, and the filtrate was concentrated under reduced pressure. The resulting residue was purified by reverse phase purification (Column: Teledyne Isco RediSep Rf® Gold Reversed-phase C18) using decreasingly polar mixtures of water and acetonitrile as eluents. Product fractions were concentrated under reduced pressure afford N1-(4-((1R,3R)-2-((3-fluorooxetan-3-yl)methyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)-3-methoxyphenyl)-N2-(3-fluoropropyl)ethane-1,2-diamine (100 mg, 54%) as a beige solid. ¹H NMR (500 MHz, DMSO-d₆, 27° C.) 1.07 (3H, d), 1.72-1.85 (2H, m), 2.60-2.66 (2H, m), 2.68-2.82 (4H, m), 3.03-3.17 (3H, m), 3.80 (3H, s), 4.44-4.67 (6H, m), 5.26 (1H, s), 5.53 (1H, br t), 5.98 (1H, dd), 6.25-6.31 (2H, m), 6.92-6.97 (1H, m), 6.98-7.03 (1H, m), 7.19 (1H, d), 7.41 (1H, d), 10.46 (1H, s). (Two hydrogen multiplet obscured by DMSO. Alkyl NH not observed). m/z: ES+ [M+H]+ 499.

Procedures used to prepare the starting material benzyl (2-((4-((1R,3R)-2-((3-fluorooxetan-3-yl)methyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)-3-methoxyphenyl)amino)ethyl)(3-fluoropropyl)carbamate are described below.

Preparation of benzyl (2-((4-((1R,3R)-2-((3-fluorooxetan-3-yl)methyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)-3-methoxyphenyl)amino)ethyl)(3-fluoropropyl)carbamate

Potassium carbonate (167 mg, 1.21 mmol) and BrettPhos 3^(rd) Generation Precatalyst (24 mg, 0.050 mmol) were added sequentially to a solution of (1R,3R)-1-(4-bromo-2-methoxyphenyl)-2-((3-fluorooxetan-3-yl)methyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole (278 mg, 0.60 mmol) and benzyl (2-aminoethyl)(3-fluoropropyl)carbamate (200 mg, 0.79 mmol) in tetrahydrofuran (8 mL) that had been degassed via sequential application of vacuum and nitrogen atmosphere (×3). The mixture was warmed to 100° C. After 18 hours, the reaction was cooled, filtered with an ethyl acetate wash, and the filtrate was concentrated under reduced pressure. The resulting residue was purified by flash column chromatography, elution gradient 0 to 50% ethyl acetate in hexanes, to afford benzyl (2-((4-((1R,3R)-2-((3-fluorooxetan-3-yl)methyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)-3-methoxyphenyl)amino)ethyl)(3-fluoropropyl)carbamate (248 mg, 64%) as a beige foam solid. m/z: ES+ [M+H]+ 633.

Example 48 Preparation of N-(2-(4-((1R,3R)-2-(2,2-difluoroethyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)-3-fluorophenoxy)ethyl)-3-fluoropropan-1-amine

Formic acid (2 mL) was added to tert-butyl (2-(4-((1R,3R)-2-(2,2-difluoroethyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)-3-fluorophenoxy)ethyl)(3-fluoropropyl)carbamate (175 mg, 0.31 mmol). After 1.5 hours the dark purple reaction was placed in the freezer. After 18 hours, the light beige matrix was removed from the freezer and warmed to room temperature, whereupon it became purple again. After 2 hours of stirring at room temperature, the reaction was slowly poured into saturated aqueous sodium bicarbonate, resulting in vigorous gas evolution. The mixture was extracted with ethyl acetate (×3). The combined organic layers were dried over sodium sulfate, filtered, and concentrated under reduced pressure to afford a yellow foam solid (121 mg). This material was purified by preparative SFC (Column: (S, S) Whelk-O1, diameter: 21.2 mm, length: 250 mm, 5 μm; flow rate: 20 mL/min) eluting with isocratic 30% (methanol containing 0.2% ammonium hydroxide) in CO₂, to afford N-(2-(4-((1R,3R)-2-(2,2-difluoroethyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)-3-fluorophenoxy)ethyl)-3-fluoropropan-1-amine (0.083 g, 58%) as a white foam solid. ¹H NMR (300 MHz, DMSO-d₆, 27° C.) 1.08 (3H, d), 1.68-1.87 (2H, m), 1.93 (1H, br s), 2.53-2.77 (5H, m), 2.85 (2H, t), 2.99-3.27 (2H, m), 4.00 (2H, t), 4.49 (2H, dt), 5.23 (1H, s), 6.02 (1H, tt), 6.54-6.67 (2H, m), 6.86 (1H, dd), 6.95-7.08 (2H, m), 7.21-7.27 (1H, m), 7.45 (1H, d), 10.64 (1H, s). m/z: ES+(M+H)+ 464.

Procedures used to prepare the starting material to tert-butyl (2-(4-((1R,3R)-2-(2,2-difluoroethyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)-3-fluorophenoxy)ethyl)(3-fluoropropyl)carbamate are described below:

Preparation of (1R,3R)-1-(4-bromo-2-fluorophenyl)-2-(2,2-difluoroethyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole

4-Bromo-2-fluorobenzaldehyde (0.469 g, 2.31 mmol) was added in one portion to a solution of (R)—N-(2,2-difluoroethyl)-1-(1H-indol-3-yl)propan-2-amine (0.5 g, 2.10 mmol) in toluene (6.30 mL) and acetic acid (0.70 mL). The light beige solution was warmed to 90° C. After 4 hours, the reaction was cooled to room temperature. The reaction was then poured into saturated aqueous sodium bicarbonate. The layers were separated, and the organic layer was washed with saturated aqueous sodium chloride, dried over sodium sulfate, filtered, and concentrated under reduced pressure. The resulting residue was purified by flash silica chromatography, elution gradient 0 to 20% ethyl acetate in hexanes, to afford (1R,3R)-1-(4-bromo-2-fluorophenyl)-2-(2,2-difluoroethyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole (0.890 g, 100%) as a 4:1 mixture of trans:cis diastereomers and a light yellow foam solid. ¹H NMR (300 MHz, DMSO-d₆, 27° C.) 1.08 (3H, d), 2.53-2.77 (3H, m), 3.08-3.24 (2H, m), 5.28 (1H, s), 5.84-6.31 (1H, m), 6.64 (1H, t), 6.98-7.10 (2H, m), 7.24-7.32 (2H, m), 7.46 (1H, d), 7.59 (1H, dd), 10.67 (1H, s). m/z: ES+(M+H)+ 423.

Preparation of tert-butyl (2-(4-((1R,3R)-2-(2,2-difluoroethyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)-3-fluorophenoxy)ethyl)(3-fluoropropyl)carbamate

Cesium carbonate (0.49 g, 1.5 mmol) and RockPhos 3rd Generation Precatalyst (0.030 g, 0.040 mmol) were added sequentially to a solution of tert-butyl (3-fluoropropyl)(2-hydroxyethyl)carbamate (0.392 g, 1.77 mmol) and (1R,3R)-1-(4-bromo-2-fluorophenyl)-2-(2,2-difluoroethyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol e (0.30 g, 0.71 mmol) in toluene (5.9 mL) that had been degassed via sequential application of vacuum and nitrogen atmosphere (×3). The mixture was warmed to 90° C. After 4 hours, the reaction was cooled and maintained at room temperature for 2.5 days. The mixture was then filtered with an ethyl acetate wash, and the filtrate was concentrated under reduced pressure. The resulting residue was purified by flash column chromatography, elution gradient 0 to 50% ethyl acetate in hexanes, to afford a faint amber foam solid (360 mg, 91%; 4:1 mixture of diastereomers). Of this material, 175 mg was purified by preparative SFC (Column: (S,S) Whelk-O1, diameter: 21.2 mm, length: 250 mm, 5 μm; flow rate: 20 mL/min) eluting with 30% (methanol containing 0.2% ammonium hydroxide) in CO₂, to afford tert-butyl (2-(4-((1R,3R)-2-(2,2-difluoroethyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)-3-fluorophenoxy)ethyl)(3-fluoropropyl)carbamate (0.089 g, 23%) as a white foam solid. ¹H NMR (300 MHz, DMSO-d₆, 27° C.) 1.07 (3H, d), 1.37 (9H, s), 1.76-1.98 (2H, m), 2.53-2.79 (3H, m), 2.99-3.25 (2H, m), 3.31-3.37 (2H, m), 3.50 (2H, br t), 4.06 (2H, br t), 4.44 (2H, dt), 5.23 (1H, s), 6.03 (1H, tt), 6.54-6.68 (2H, m), 6.88 (1H, dd), 6.95-7.08 (2H, m), 7.22-7.27 (1H, m), 7.45 (1H, d), 10.63 (1H, s). m/z: ES+(M+H)+ 564.

Example 49 Preparation of N1-(4-((1R,3R)-2-(2,2-difluoroethyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)-3,5-difluorophenyl)-N2-(3-fluoropropyl)-N1-methylethane-1,2-diamine

Benzyl (2-((4-((1R,3R)-2-(2,2-difluoroethyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)-3,5-difluorophenyl)(methyl)amino)ethyl)(3-fluoropropyl)carbamate (159 mg, 0.25 mmol) was dissolved in ethanol (1.5 mL), and the reaction flask was evacuated and backfilled with nitrogen. Then palladium on carbon (10 wt %; 27 mg, 0.025 mmol) was added, and the reaction was evacuated and backfilled with hydrogen (balloon). The reaction was stirred under these conditions for two hours at ambient temperature. The mixture was then filtered through diatomaceous earth, and the filtrate was concentrated under reduced pressure. The resulting residue was purified by preparative SFC (Column: (S,S) Whelk-O1, Diameter: 30 mm, Length: 100 mm, 5 μm; Flow rate: 120 mL/min), eluting with 25% (methanol containing 0.2% NH₄OH) in CO₂, to afford N1-(4-((1R,3R)-2-(2,2-difluoroethyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)-3,5-difluorophenyl)-N2-(3-fluoropropyl)-N1-methyl ethane-1,2-diamine (61 mg, 49%) as a beige crystalline solid. ¹H NMR (300 MHz, DMSO-d₆, 27° C.) 1.09 (3H, d), 1.64-1.86 (3H, m), 2.55-2.78 (6H, m), 2.83 (1H, dd), 2.89-2.93 (3H, m), 2.94-3.12 (1H, m), 3.33-3.44 (3H, m), 4.48 (2H, tt), 5.10 (1H, s), 5.83 (1H, tt), 6.29 (2H, d), 6.91-7.02 (2H, m), 7.17-7.23 (1H, m), 7.39 (1H, d), 10.54 (1H, s). m/z: ES+ [M+H]+ 495.

Procedures used to prepare benzyl (2-((4-((1R,3R)-2-(2,2-difluoroethyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)-3,5-difluorophenyl)(methyl)amino)ethyl)(3-fluoropropyl)carbamate are described below.

Preparation of (1R,3R)-1-(4-bromo-2,6-difluorophenyl)-2-(2,2-difluoroethyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole

4-Bromo-2,6-difluorobenzaldehyde (510 mg, 2.31 mmol) was added to a solution of (R)—N-(2,2-difluoroethyl)-1-(1H-indol-3-yl)propan-2-amine (550 mg, 2.31 mmol) and in acetic acid (1.16 mL) and toluene (10.4 mL). The reaction was stirred at 85° C. for five hours and then concentrated under reduced pressure. The resulting residue was purified by flash silica chromatography, elution gradient 0 to 100% ethyl acetate in hexanes, to afford (1R,3R)-1-(4-bromo-2,6-difluorophenyl)-2-(2,2-difluoroethyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole (770 mg, 97%) as a 4:1 ratio of trans:cis diastereomers and a beige oily solid. 1H for trans isomer: ¹H NMR (300 MHz, DMSO-d₆, 27° C.) 1.10 (3H, d), 2.54-2.68 (2H, m), 2.78-2.90 (1H, m), 3.01-3.22 (1H, m), 3.33-3.45 (1H, m), 5.19-5.33 (1H, m), 5.91 (1H, tt), 6.91-7.05 (2H, m), 7.19-7.23 (1H, m), 7.39-7.47 (3H, m), 10.57-10.68 (1H, m). m/z: ES+ [M+H]+ 441.

Preparation of tert-butyl (2-(((benzyloxy)carbonyl)(3-fluoropropyl)amino)ethyl)(methyl)carbamate

A solution of 1-fluoro-3-iodopropane (2.40 g, 12.77 mmol) in acetonitrile (3 ml) was added to a solution of tert-butyl (2-aminoethyl)(methyl)carbamate (3.71 g, 21.3 mmol) and potassium carbonate (5.88 g, 42.6 mmol) in acetonitrile (14 mL). The reaction was stirred at ambient temperature for 18 hours and then filtered with an acetonitrile wash. The filtrate was concentrated under reduced pressure to afford a white oily solid. This solid was dissolved in dichloromethane (42 mL), cooled to 0° C., and N,N-diisopropylethylamine (5.2 mL, 29.8 mmol) was added followed by dropwise addition of benzyl chloroformate (3.34 ml, 23.4 mmol). The reaction was warmed to ambient temperature, and, after 5 hours, the reaction mixture was diluted with dichloromethane and washed with water. The organic layer was extracted with dichloromethane (×2), and the combined organic layers were dried over sodium sulfate, filtered, and concentrated under reduced pressure. The resulting residue was purified by flash silica gel chromatography, eluting with 0 to 50% ethyl acetate in hexanes, to afford tert-butyl (2-(((benzyloxy)carbonyl)(3-fluoropropyl)amino)ethyl)(methyl)carbamate (3.30 grams, 42% yield) as a clear oil. ¹H NMR (300 MHz, DMSO-d₆, 27° C.) 1.36 (9H, s), 1.76-1.97 (2H, m), 2.66-2.80 (3H, m), 3.25-3.37 (6H, m), 4.33-4.59 (2H, m), 5.06 (2H, s), 7.29-7.41 (5H, m).

Preparation of benzyl (3-fluoropropyl)(2-(methylamino)ethyl)carbamate

Trifluoroacetic acid (6.90 mL, 89.6 mmol) was added to a solution of benzyl (2-((tert-butoxycarbonyl)(methyl)amino)ethyl)(3-fluoropropyl)carbamate (3.30 g, 8.96 mmol) in dichloromethane (32 mL). The reaction was stirred at ambient temperature for 18 hours and then diluted with DCM. The solution was washed with saturated aqueous sodium bicarbonate, and the aqueous layer was extracted with dichloromethane. The combined organic layers were dried over sodium sulfate, filtered, and concentrated under reduced pressure to afford benzyl (3-fluoropropyl)(2-(methylamino)ethyl)carbamate (2.35 grams, 98%) as a clear oil. ¹H NMR (300 MHz, DMSO-d₆, 27° C.) 1.79-1.99 (2H, m), 2.28-2.41 (3H, m), 2.61-2.80 (2H, m), 3.28-3.41 (4H, m), 4.45 (2H, dt), 4.59-4.74 (1H, br s), 5.08 (2H, s), 7.30-7.41 (5H, m).

Preparation of benzyl (2-((4-((1R,3R)-2-(2,2-difluoroethyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)-3,5-difluorophenyl)(methyl)amino)ethyl)(3-fluoropropyl)carbamate

Potassium carbonate (241 mg, 1.74 mmol) and BrettPhos 3^(rd) Generation Precatalyst (35 mg, 0.070 mmol) were added sequentially to a solution of (1R,3R)-1-(4-bromo-2,6-difluorophenyl)-2-(2,2-difluoroethyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole (385 mg, 0.87 mmol) and benzyl (3-fluoropropyl)(2-(methylamino)ethyl)carbamate (351 mg, 1.31 mmol) in dioxane (4.3 mL) that had been degassed via sequential application of vacuum and nitrogen atmosphere (×3). The mixture was warmed to 70° C. After 18 hours, the reaction was cooled, filtered with an ethyl acetate wash, and the filtrate was concentrated under reduced pressure. The resulting residue was purified by flash column chromatography, elution gradient 0 to 50% ethyl acetate in hexanes, to afford benzyl (2-((4-((1R,3R)-2-(2,2-difluoroethyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)-3,5-difluorophenyl)(methyl)amino)ethyl)(3-fluoropropyl)carbamate (159 mg, 29%) as an orange gum. m/z: ES+ [M+H]+ 629.

Examples 50-78 (Table G below) were prepared using methods analogous to those described above.

TABLE G LCMS Example Structure Name 1H NMR [M + H]

N-(2-(3,5- difluoro-4- ((1R,3R)-2-(2- fluoro-3- methoxy-2- methylpropyl)- 3-methyl- 2,3,4,9- tetrahydro-1H- pyrido[3,4- b]indol-1- yl)phenoxy) ethyl)-3- fluoropropan- 1-amine formic acid salt ¹H NMR (500 MHz, CDCl₃, 27° C.) 1.10 (3H, d), 1.18 (3H, d), 1.88-2.06 (2H, m), 2.50 (1H, dd), 2.61 (1H, dd), 2.89-3.01 (3H, m), 3.03-3.11 (1H, m), 3.12-3.18 (2H, m), 3.28-3.36 (4H, m), 3.34-3.46 (1H, m), 3.56-3.66 (1H, m), 4.11 (2H, t), 4.38-4.49 (1H, m), 4.48-4.61 (1H, m), 5.21 (1H, s), 6.39 (2H, d), 7.02-7.15 (2H, m), 7.20 (1H, dd), 7.48-7.53 (1H, m), 7.79 (1H, s), 8.23 (1H, s). (2 exchangeables not observed) 522 51

N-(2-(3,5- difluoro-4- ((1R,3R)-2-(2- fluoro-3- methoxy-2- methylpropyl)- 3-methyl- 2,3,4,9- tetrahydro-1H- pyrido[3,4- b]indol-1- yl)phenoxy) ethyl)-3- fluoropropan- 1-amine formic acid salt ¹H NMR (500 MHz, CDCl₃, 27° C.) 1.10 (3H, d), 1.19 (3H, d), 1.92-2.04 (2H, m), 2.49 (1H, dd), 2.61 (1H, dd), 2.92-3.30 (3H, m), 3.04-3.11 (1H, m), 3.14-3.24 (3H, m), 3.29 (3H, s), 3.43-3.48 (1H, m), 3.61-3.69 (1H, m), 4.11 (2H, t), 4.40-4.47 (1H, m), 4.49-4.57 (1H, m), 5.16 (1H, s), 6.40 (2H, d), 7.02-7.14 (2H, m), 7.15-7.22 (1H, m), 7.46- 7.57 (1H, m), 7.79 (1H, s), 8.22 (1H, s). (2 exchangeables not observed) 522 52

3-(3,5- difluoro-4- ((1R,3R)-2-(2- fluoro-2- methylpropyl)- 3-methyl- 2,3,4,9- tetrahydro-1H- pyrido[3,4- b]indol-1- yl)phenoxy)-2- ((3-fluoro- propyl)amino) propan-1-ol ¹H NMR (500 MHz, CDCl₃, 27° C.) 1.09 (3H, d), 1.16-1.27 (6H, m), 1.83-1.94 (2H, m), 2.39 (1H, dd), 2.53- 2.62 (3H, m), 2.78-2.9 (3H, m), 3.01-3.10 (2H, m), 3.54 (1H, dd), 3.62-3.69 (1H, m), 3.72 (1H, dd), 3.88-3.99 (2H, m), 4.53 (2H, dt), 5.19 (1H, s), 6.41 (2H, d), 7.05-7.11 (2H, m), 7.17-7.21 (1H, m), 7.48-7.52 (1H, m), 7.56 (1H, s). (One proton not observed). 522 53

3-(3,5- difluoro-4- ((1R,3R)-2-(2- fluoro-2- methylpropyl)- 3-methyl- 2,3,4,9- tetrahydro-1H- pyrido[3,4- b]indol-1- yl)phenoxy)-2- ((3-fluoro- propyl)amino) propan-1-ol ¹H NMR (500 MHz, CDCl₃, 27° C.) 1.09 (3H, d), 1.16-1.27 (6H, m), 1.83-1.94 (2H, m), 2.39 (1H, dd), 2.53- 2.62 (3H, m), 2.78-2.9 (3H, m), 3.01-3.10 (2H, m), 3.54 (1H, dd), 3.62-3.69 (1H, m), 3.72 (1H, dd), 3.88-3.99 (2H, m), 4.53 (2H, dt), 5.19 (1H, s), 6.41 (2H, d), 7.05-7.11 (2H, m), 7.17-7.21 (1H, m), 7.48- 7.52 (1H, m), 7.56 (1H, s). (One proton not observed). 522 54

N1-(4- ((1R,3R)-2- (2,2- difluoroethyl)- 3-methyl- 2,3,4,9- tetrahydro-1H- pyrido[3,4- b]indol-1-yl)- 3,5-difluoro- phenyl)- N2-(3-fluoro- propyl)ethane- 1,2-diamine ¹H NMR (300 MHz, DMSO, 27° C.) 1.09 (3H, d), 1.67-1.88 (2H, m), 2.55-2.71 (5H, m), 2.83 (1H, dd), 2.93- 3.11 (3H, m), 3.36-3.44 (1H, m), 4.50 (2H, dt), 5.07 (1H, s), 5.81 (1H, tt), 6.18 (3H, d), 6.89-7.03 (2H, m), 7.11-7.29 (3H, m), 7.38 (1H, d), 10.54 (1H, s). 481 55

N-(2-(4- ((1R,3R)-2- (2,2-difluoro- propyl)-3- methyl- 2,3,4,9- tetrahydro-1H- pyrido[3,4- b]indol-1-yl)- 3-fluoro- phenoxy) ethyl)-3- fluoropropan- 1-amine ¹H NMR (500 MHz, DMSO, 27° C.) 1.07 (3H, d), 1.64 (3H, t), 1.71-1.82 (3H, m), 2.51-2.56 (1H, m), 2.57- 2.66 (3H, m), 2.70 (1H, dd), 2.84 (2H, t), 2.98-3.1 (1H, m), 3.19-3.27 (1H, m), 3.99 (2H, t), 4.49 (2H, dt), 5.24 (1H, s), 6.53 (1H, t), 6.63 (1H, dd), 6.86 (1H, dd), 6.95-7.01 (1H, m), 7.02-7.07 (1H, m), 7.24 (1H, d), 7.45 (1H, d), 10.68 (1H, s). 478 56

N-(2-(4- ((1R,3R)-2- (2,2- difluoroethyl)- 3-methyl- 2,3,4,9- tetrahydro-1H- pyrido[3,4- b]indol-1- yl)phenoxy) ethyl)-3- fluoropropan- 1-amine ¹H NMR (300 MHz, DMSO, 27° C.) 1.07 (3H, d), 1.68-1.87 (3H, m), 2.53-2.75 (5H, m), 2.85 (2H, br t), 3.00- 3.19 (2H, m), 3.97 (2H, t), 4.49 (2H, dt), 4.91 (1H, s), 6.05 (1H, tt), 6.83-6.92 (2H, m), 6.93-7.00 (1H, m), 7.00-7.08 (1H, m), 7.08-7.14 (2H, m), 7.22-7.30 (1H, m), 7.43 (1H, d), 10.67 (1H, s) 446 57

N-(2-(4- ((1R,3R)-2- (2,2-difluoro- propyl)- 3-methyl- 2,3,4,9- tetrahydro-1H- pyrido[3,4- b]indol-1- yl)phenoxy) ethyl)-3- fluoropropan- 1-amine ¹H NMR (500 MHz, DMSO, 27° C.) 1.08 (3H, d), 1.68 (3H, t), 1.73-1.83 (2H, m), 1.87 (1H, br s), 2.59-2.67 (4H, m), 2.85 (2H, t), 3.02-3.17 (2H, m), 3.97 (2H, t), 4.49 (2H, dt), 4.95 (1H, s), 6.89 (2H, d), 6.98 (1H, t), 7.02-7.07 (1H, m), 7.10 (2H, d), 7.28 (1H, d), 7.43 (1H, d), 10.78 (1H, s). (One proton not observed). 460 58

2,2-difluoro-3- ((1R,3R)-1-(4- (2-((3- fluoropropyl) amino)ethoxy)- 2-methoxy- phenyl)-3- methyl- 1,3,4,9- tetrahydro-2H- pyrido[3,4- b]indol-2- yl)propan-1-ol ¹H NMR (400 MHz, DMSO, 27° C.) 1.05 (3H, d), 1.71-1.86 (2H, m), 2.59-2.74 (4H, m), 2.85 (2H, t), 3.01-3.16 (1H, m), 3.66-3.89 (5H, m), 3.98 (2H, t), 4.50 (2H, dt), 5.20 (1H, t), 5.32 (1H, s), 6.35 (1H, dd), 6.43 (1H, d), 6.61 (1H, d), 6.94-7.05 (2H, m), 7.20 (1H, d), 7.43 (1H, d), 10.54 (1H, s). (3 protons not observed). 506 59

2,2-difluoro-3- ((1R,3R)-1-(4- ((2-((3- fluoropropyl) amino)ethyl) amino)-2- methoxy- phenyl)-3- methyl- 1,3,4,9- tetrahydro-2H- pyrido[3,4- b]indol-2- yl)propan-1-ol 1H NMR (500 MHz, CDCl₃, 27° C.) 1.18 (3H, d), 1.82-1.94 (2H, m), 2.59-2.66 (1H, m), 2.78 (2H, t), 2.87-2.91 (2H, m), 2.91-3.04 (2H, m), 3.10-3.17 (1H, m), 3.18-3.22 (2H, m), 3.54-3.90 (6H, m), 4.54 (2H, dt), 5.26 (1H, s), 6.12 (1H, dd), 6.21 (1H, d), 6.74 (1H, d), 7.07-7.15 (2H, m), 7.19-7.23 (1H, m), 7.26 (1H, s), 7.49-7.54 (2H, m). (2 protons not observed). 505 60

N1-(4- ((1R,3R)-2-((1- fluorocyclo- propyl)methyl)- 3-methyl- 2,3,4,9- tetrahydro-1H- pyrido[3,4- b]indol-1-yl)- 3-methoxy- phenyl)-N2- (3-fluoro- propyl)ethane- 1,2-diamine ¹H NMR (300 MHz, DMSO, 27° C.) 0.57-0.68 (2H, m), 0.86-0.99 (2H, m), 1.04 (3H, d), 1.67-1.87 (3H, m), 2.53-2.64 (4H, m), 2.68 (2H, t), 2.79 (1H, dd), 2.99-3.12 (3H, m), 3.44-3.55 (1H, m), 3.81 (3H, s), 4.50 (2H, dt), 5.22 (1H, s), 5.48 (1H, t), 6.00 (1H, dd), 6.27 (1H, d), 6.45 (1H, d), 6.88-7.00 (2H, m), 7.16-7.21 (1H, m), 7.38 (1H, d), 10.24 (1H, s). 483 61

N1-(4- ((1R,3R)-2- (2,2- difluoroethyl)- 3-methyl- 2,3,4,9- tetrahydro-1H- pyrido[3,4- b]indol-1-yl)- 3-methoxy- phenyl)- N2-(3-fluoro- propyl)ethane- 1,2-diamine ¹H NMR (500 MHz, CDCl₃, 27° C.) 1.14 (3H, d), 1.82-1.94 (2H, m), 2.53-2.6 (1H, m), 2.71-2.82 (3H, m), 2.86-3.03 (4H, m), 3.19 (2H, q), 3.42-3.5 (1H, m), 3.90 (3H, s), 4.18 (1H, t), 4.54 (2H, dt), 5.22 (1H, s), 5.64-5.93 (1H, m), 6.08 (1H, dd), 6.23 (1H, d), 6.74 (1H, d), 7.07-7.14 (2H, m), 7.2-7.23 (1H, m), 7.49- 7.52 (1H, m), 7.56 (1H, s). (One proton not observed). 475 62

3-fluoro-N-(2- ((4-fluoro-5- ((1R,3R)-2-((3- fluorooxetan- 3-yl)methyl)- 3-methyl- 2,3,4,9- tetrahydro-1H- pyrido[3,4- b]indol-1- yl)pyridin-2- yl)oxy)ethyl) propan-1-amine ¹H NMR (500 MHz, CDCl₃, 27° C.) 1.21 (3H, d), 1.82-1.94 (2H, m), 2.57-2.63 (1H, m), 2.75 (1H, dd), 2.80 (2H, t), 2.92-2.99 (3H, m), 3.19 (1H, dd), 3.27-3.33 (1H, m), 4.33-4.37 (2H, m), 4.39 (1H, dd), 4.52 (2H, dt), 4.69 (1H, dd), 4.71-4.75 (1H, m), 4.83 (1H, dd), 5.36 (1H, d), 6.47 (1H, d), 7.11-7.15 (1H, m), 7.16-7.2 (1H, m), 7.29 (1H, dt), 7.50 (1H, d), 7.52-7.54 (1H, m), 7.68 (1H, s). (One proton not observed). 489 63

N-(2-((5- ((1R,3R)-2- (2,2- difluoroethyl)- 3-methyl- 2,3,4,9- tetrahydro-1H- pyrido[3,4- b]indol-1-yl)- 4-methyl- pyridin-2- yl)oxy)ethyl)- 3-fluoro- propan-1-amine ¹H NMR (500 MHz, CDCl₃, 27° C.) 1.13 (3H, d), 1.81-1.92 (2H, m), 2.19 (3H, s), 2.65 (1H, ddd), 2.73-2.84 (3H, m), 2.93-3.04 (4H, m), 3.45 (1H, h), 4.29-4.36 (2H, m), 4.51 (2H, dt), 4.89 (1H, s), 5.58 (1H, tt), 6.54 (1H, s), 7.08- 7.16 (2H, m), 7.21-7.24 (1H, m), 7.49-7.52 (1H, m), 7.66 (1H, s), 7.83 (1H, s). (One proton not observed). 461 64

2,2-difluoro-3- ((1R,3R)-1-(6- (2-((3- fluoropropyl) amino)ethoxy)- 4-methoxy- pyridin-3-yl)- 3-methyl- 1,3,4,9- tetrahydro-2H- pyrido[3,4- b]indol-2- yl)propan-1-ol 1H NMR (500 MHz, CDCl₃, 27° C.) 1.21 (3H, d), 1.83-1.95 (2H, m), 2.56-2.65 (1H, m), 2.79-2.87 (3H, m), 2.90-2.98 (3H, m), 3.15-3.25 (1H, m), 3.51 (1H, s), 3.83- 3.92 (5H, m), 4.32-4.40 (2H, m), 4.53 (2H, dt), 5.29 (1H, s), 6.27 (1H, s), 7.09-7.13 (1H, m), 7.14-7.18 (1H, m), 7.24 (1H, t), 7.44 (1H, s), 7.50-7.53 (1H, m), 7.67 (1H, s). (Two protons not observed). 507 65

2,2-difluoro-3- ((1R,3R)-1-(6- ((2-((3- fluoropropyl) amino)ethyl) amino)-4- methoxy- pyridin-3-yl)- 3-methyl- 1,3,4,9- tetrahydro-2H- pyrido[3,4- b]indol-2- yl)propan-1-ol ¹H NMR (500 MHz, CDCl₃, 27° C.) 1.20 (3H, d), 1.81-1.93 (2H, m), 2.60 (1H, dd), 2.78 (2H, t), 2.84-2.90 (3H, m), 2.91-3.01 (1H, m), 3.13-3.23 (1H, m), 3.38 (2H, q), 3.53-3.62 (1H, m), 3.76-3.90 (5H, m), 4.53 (2H, dt), 4.92- 4.98 (1H, m), 5.19 (1H, s), 5.89 (1H, s), 7.08-7.16 (2H, m), 7.21-7.25 (1H, m), 7.42 (1H, s), 7.50 (1H, d), 7.62 (1H, s). (Two protons not observed). 506 66

N1-(5- ((1R,3R)-2-((3- fluorooxetan- 3-yl)methyl)- 3-methyl- 2,3,4,9- tetrahydro-1H- pyrido[3,4- b]indol-1-yl)- 4-methoxy- pyridin-2- yl)-N2-(3- fluoropropyl) ethane-1,2- diamine ¹H NMR (500 MHz, DMSO, 27° C.) 1.02 (3H, d), 1.60-1.73 (2H, m), 2.47-2.73 (7H, m), 3.03-3.18 (3H, m), 3.73 (3H, s), 4.34-4.61 (6H, m), 5.13 (1H, s), 5.98 (1H, s), 6.25 (1H, t), 6.84 (1H, s), 6.89 (1H, t), 6.95 (1H, t), 7.13 (1H, d), 7.35 (1H, d), 10.49 (1H, s). (2H obscured by solvent). 500 67

N1-(5- ((1R,3R)-2- (2,2- difluoroethyl)- 3-methyl- 2,3,4,9- tetrahydro-1H- pyrido[3,4- b]indol-1-yl)- 4-methoxy- pyridin-2- yl)-N2-(3- fluoropropyl) ethane-1,2- diamine ¹H NMR (500 MHz, CDCl₃, 27° C.) 1.15 (3H, d), 1.80-1.91 (2H, m), 2.53 (1H, ddd), 2.68-2.78 (3H, m), 2.80 (1H, dd), 2.83-2.87 (2H, m), 2.97-3.08 (1H, m), 3.34-3.44 (3H, m), 3.90 (3H, s), 4.52 (2H, dt), 4.90 (1H, t), 5.12 (1H, s), 5.79-6.04 (2H, m), 7.07-7.15 (2H, m), 7.20-7.24 (1H, m), 7.40 (1H, s), 7.48-7.52 (1H, m), 7.71 (1H, s). (One proton not observed). 476 68

N1-(5- ((1R,3R)-2- (2,2-difluoro- propyl)-3- methyl- 2,3,4,9- tetrahydro-1H- pyrido[3,4- b]indol-1-yl)- 4-methoxy- pyridin-2- yl)-N2-(3- fluoropropyl) ethane-1,2- diamine ¹H NMR (500 MHz, CDCl₃, 27° C.) 1.14 (3H, d), 1.62 (3H, t), 1.81-1.92 (2H, m), 2.54 (1H, ddd), 2.69-2.82 (4H, m), 2.84-2.87 (2H, m), 2.92 (1H, dd), 3.37 (2H, q), 3.45- 3.53 (1H, m), 3.88 (3H, s), 4.52 (2H, dt), 4.88 (1H, t), 5.20 (1H, s), 5.90 (1H, s), 7.06-7.14 (2H, m), 7.21-7.24 (1H, m), 7.46 (1H, s), 7.48-7.51 (1H, m), 7.70 (1H, s). (One proton not observed). 490 69

2,2-difluoro-3- ((1S,3R)-1-(5- (2-((3- fluoropropyl) amino)ethoxy) pyrazin-2- yl)-3-methyl- 1,3,4,9- tetrahydro-2H- pyrido[3,4- b]indol-2- yl)propan-1-ol ¹H NMR (500 MHz, CDCl₃, 27° C.) 1.28 (3H, d), 1.84-1.95 (2H, m), 2.64 (1H, dd), 2.72 (1H, dd), 2.82 (2H, t), 2.94-3.03 (3H, m), 3.22- 3.33 (2H, m), 3.85-3.94 (1H, m), 3.96-4.04 (1H, m), 4.36- 4.45 (2H, m), 4.53 (2H, dt), 5.20 (1H, s), 7.10-7.14 (1H, m), 7.16-7.22 (1H, m), 7.35 (1H, d), 7.52 (1H, d), 8.00 (1H, s), 8.19 (1H, d), 8.25 (1H, s). (2 protons not observed). 478 70

N-(2-((5- ((1S,3R)-2- (2,2- difluoroethyl)- 3-methyl- 2,3,4,9- tetrahydro-1H- pyrido[3,4- b]indol-1- yl)pyrazin-2- yl)oxy)ethyl)- 3-fluoro- propan-1-amine ¹H NMR (500 MHz, CDCl3, 27° C.) 1.31 (3H, d), 1.84-1.95 (2H, m), 2.63 (1H, ddd), 2.75 (1H, dd), 2.78-2.86 (3H, m), 2.99-3.04 (2H, m), 3.13-3,25 (1H, m), 3.30-3.38 (1H, m), 4.38-4.46 (2H, m), 4.53 (2H, dt), 5.06 (1H, s), 5.72-5.98 (1H, m), 7.09 (1H, ddd), 7.16 (1H, ddd), 7.34 (1H, dt), 7.49 (1H, d), 8.17 (1H, d), 8.37 (1H, dd), 8.41 (1H, s). (One proton not observed). 448 71

N1-(5- ((1S,3R)-2- (2,2- difluoroethyl)- 3-methyl- 2,3,4,9- tetrahydro-1H- pyrido[3,4- b]indol-1- yl)pyrazin-2- yl)-N2-(3- fluoropropyl) ethane-1,2- diamine ¹H NMR (500 MHz, CDCl₃, 27° C.) 1.26 (3H, d), 1.81-1.93 (2H, m), 2.62 (1H, ddd), 2.76-2.83 (4H, m), 2.84- 2.92 (2H, m), 3.09-3.20 (1H, m), 3.35-3.46 (3H, m), 4.53 (2H, dt), 4.96 (1H, s), 5.09 (1H, t), 5.81 (1H, tt), 7.08 (1H, td), 7.12-7.16 (1H, m), 7.30-7.33 (1H, m), 7.49 (1H, d), 7.83 (1H, d), 8.22 (1H, s), 8.32 (1H, s). (One proton not observed). 447 72

N-(2-(3,5- difluoro-4- ((1R,3R)-2-((3- (fluoromethyl) oxetan-3- yl)methyl)-3- methyl- 2,3,4,9- tetrahydro-1H- pyrido[3,4- b]indol-1- yl)phenoxy) ethyl)-3- fluoropropan- 1-amine ¹H NMR (500 MHz, CDCl₃, 27° C.) 1.12 (3H, d), 1.85 (1H, ddd), 1.91 (1H, ddd), 2.61 (1H, ddd), 2.66 (1H, d), 2.81 (2H, t), 2.96-3.00 (2H, m), 3.00-3.06 (1H, m), 3.06- 3.12 (2H, m), 4.00 (2H, t), 4.16 (1H, dd), 4.34 (1H, d), 4.46-4.50 (3H, m), 4.50-4.65 (2H, m), 4.72 (1H, dd), 5.05 (1H, s), 6.37-6.45 (2H, m), 7.05-7.16 (2H, m), 7.17-7.23 (1H, m), 7.50 (1H, dd), 7.60 (1H, s). 520 73

3-fluoro-N-(2- (3-methoxy-4- ((1R,3R)-3- methyl-2- (2,2,2- trifluoroethyl)- 2,3,4,9- tetrahydro-1H- pyrido[3,4- b]indol-1- yl)phenoxy) ethyl)propan- 1-amine ¹H NMR (500 MHz, DMSO, 27° C.) 1.06 (3H, d), 1.77 (2H, dt), 2.51-2.59 (2H, m), 2.60-2.67 (2H, m), 2.73 (1H, dd), 2.84 (2H, t), 2.92 (1H, dd), 3.37-3.49 (1H, m), 3.83 (3H, s), 3.97 (2H, t), 4.44 (1H, t), 4.53 (1H, t), 5.30 (1H, s), 6.34 (1H, dd), 6.45 (1H, d), 6.61 (1H, d), 6.95 (1H, td), 7.01 (1H, ddd), 7.14-7.26 (1H, m), 7.41 (1H, d), 10.52 (1H, s). (One proton not observed NH). 494 74

N-(2-(4- ((1R,3R)-2- (2,2-difluoro- propyl)-3- methyl- 2,3,4,9- tetrahydro-1H- pyrido[3,4- b]indol-1-yl)- 3-methoxy- phenoxy) ethyl)-3- fluoropropan- 1-amine 1H NMR (500 MHz, DMSO, 27° C.) 1.04 (3H, d), 1.63 (3H, t), 1.77 (2H, dt), 2.52 (2H, s), 2.60-2.69 (3H, m), 2.71 (1H, dd), 2.83 (2H, t), 2.89-3.06 (1H, m), 3.84 (3H, s), 3.96 (2H, t), 4.44 (1H, t), 4.53 (1H, t), 5.27 (1H, s), 6.34 (1H, dd), 6.44 (1H, d), 6.61 (1H, d), 6.95 (1H, td), 6.97- 7.04 (1H, m), 7.14-7.24 (1H, m), 7.41 (1H, d), 10.50 (1H, s). (One proton not observed NH). 490 75

N-(2-((5- ((1R,3R)-2- (2,2- difluoroethyl)- 3-methyl- 2,3,4,9- tetrahydro-1H- pyrido[3,4- b]indol-1-yl)- 6-methoxy- pyridin-2- yl)oxy)ethyl)- 3-fluoro- propan-1-amine ¹H NMR (500 MHz, CDCl₃, 27° C.) 1.16 (3H, d), 1.89 (2H, dddd), 2.57 (1H, ddd), 2.66-2.78 (1H, m), 2.81 (2H, t), 2.90 (1H, ddd), 2.96- 3.09 (3H, m), 3.38 (1H, td), 4.03 (3H, s), 4.38-4.43 (2H, m), 4.48 (1H, t), 4.58 (1H, t), 5.13 (1H, s), 5.84 (1H, tdd), 6.19 (1H, d), 7.08-7.12 (1H, m), 7.12-7.16 (1H, m), 7.17 (1H, d), 7.21-7.25 (1H, m), 7.49- 7.54 (1H, m), 7.68 (1H, s). (1 exchangeable proton not observed). 477 76

N1-(5- ((1R,3R)-2- (2,2- difluoroethyl)- 3-methyl- 2,3,4,9- tetrahydro-1H- pyrido[3,4- b]indol-1-yl)- 6-methoxy- pyridin-2- yl)-N2-(3- fluoropropyl) ethane-1,2- diamine ¹H NMR (500 MHz, CDCl₃, 27° C.) 1.15 (3H, d), 1.86 (2H, dddd), 2.53 (1H, ddd), 2.73-2.83 (4H, m), 2.82- 2.87 (2H, m), 3.02 (1H, qd), 3.33-3.45 (3H, m), 3.90 (3H, s), 4.47 (1H, t), 4.57 (1H, t), 4.90 (1H, t), 5.12 (1H, s), 5.74-6.05 (2H, m), 7.07-7.11 (1H, m), 7.11-7.15 (1H, m), 7.22 (1H, ddd), 7.40 (1H, s), 7.48-7.51 (1H, m), 7.71 (1H, s). (1 exchangeable proton not observed). 476 77

N-(2-((5- ((1R,3R)-2- (2,2-difluoro- propyl)-3- methyl- 2,3,4,9- tetrahydro-1H- pyrido[3,4- b]indol-1-yl)- 6-methoxy- pyridin-2- yl)oxy)ethyl)- 3-fluoro- propan-1-amine ¹H NMR (500 MHz, CDCl₃, 27° C.) 1.15 (3H, d), 1.58 (3H, t), 1.89 (2H, dddd), 2.58 (1H, ddd), 2.64-2.75 (1H, m), 2.81 (2H, t), 2.86 (1H, dd), 2.91-2.98 (1H, m), 2.98-3.04 (2H, m), 3.46 (1H, h), 4.02 (3H, s), 4.35-4.45 (2H, m), 4.48 (1H, t), 4.58 (1H, t), 5.20 (1H, s), 6.19 (1H, d), 7.09 (1H, td), 7.13 (1H, td), 7.18 (1H, d), 7.22-7.25 (1H, m), 7.46-7.59 (1H, m), 7.75 (1H, s). (1 exchangeable proton not observed). 491 78

N1-(5- ((1R,3R)-2- (2,2-difluoro- propyl)-3- methyl- 2,3,4,9- tetrahydro-1H- pyrido[3,4- b]indol-1-yl)- 6-methoxy- pyridin-2- yl)-N2-(3- fluoropropyl) ethane-1,2- diamine ¹H NMR (500 MHz, CDCl₃, 27° C.) 1.13 (3H, d), 1.57 (3H, t), 1.87 (2H, dddd), 2.51-2.63 (1H, m), 2.70 (1H, q), 2.77 (2H, t), 2.86 (2H, t), 2.88-3 (2H, m), 3.29-3.44 (2H, m), 3.49 (1H, h), 3.96 (3H, s), 4.53 (2H, dt), 4.72 (1H, t), 5.15 (1H, s), 5.83 (1H, d), 7.01 (1H, d), 7.04-7.16 (2H, m), 7.22 (1H, dt), 7.42- 7.55 (1H, m), 7.72 (1H, s). (1 exchangeable proton not observed). 490 

The invention claimed is:
 1. A compound, or a pharmaceutically acceptable salt thereof, wherein the compound is N-(2-((5-((1R,3R)-2-(2,2-difluoroethyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)-4-methoxypyridin-2-yl)oxy)ethyl)-3-fluoropropan-1-amine, which compound has the following structure:


2. A pharmaceutical composition, which comprises the compound according to claim 1, or a pharmaceutically acceptable salt thereof, in association with a pharmaceutically-acceptable excipient.
 3. A compound, wherein the compound is N-(2-((5-(1R,3R)-2-(2,2-difluoroethyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)-4-methoxypyridin-2-yl)oxy)ethyl)-3-fluoropropan-1-amine.
 4. A pharmaceutical composition, which comprises the compound according to claim 3, in association with a pharmaceutically-acceptable excipient.
 5. A pharmaceutically acceptable salt of N-(2-((5-((1R,3R)-2-(2,2-difluoroethyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)-4-methoxypyridin-2-yl)oxy)ethyl)-3-fluoropropan-1-amine.
 6. A pharmaceutical composition, which comprises the salt according to claim 5, in association with a pharmaceutically-acceptable excipient.
 7. A pharmaceutically acceptable salt, wherein the pharmaceutically acceptable salt is the 2-methoxybenzoate salt of N-(2-((5-((1R,3R)-2-(2,2-difluoroethyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)-4-methoxypyridin-2-yl)oxy)ethyl)-3-fluoropropan-1-amine.
 8. A pharmaceutical composition, which comprises the salt according to claim 7, in association with a pharmaceutically-acceptable excipient. 